U.S. Route 1 in Maryland

U.S. Route 1 (US 1) is the easternmost and longest of the major north–south routes of the older 1920s era United States Numbered Highway System, running from Key West, Florida, to Fort Kent, Maine. In the U.S. state of Maryland, it runs 81 mi from the Washington, D.C. line to the Pennsylvania state line near the town of Rising Sun.

US 1 is paralleled by several major highways as it passes through Maryland, including Interstate 95 (I-95), the Baltimore–Washington Parkway (B–W Parkway), US 29, and US 301. Thus, US 1 has lost its significance as a long distance route through the state. It is often congested, however, because it remains a major route in the individual towns it traverses.

Prince George's County
US 1 leaves the District of Columbia as Rhode Island Avenue NE and just simply becomes Rhode Island Avenue, a four-lane divided street with parking through a downtown-like commercial area, right after crossing the intersection of Eastern Avenue NE (the Maryland–DC line) and entering the city of Mount Rainier in Prince George's County. US 1 then meets the intersections of 34th and Perry streets at a roundabout (which was finished being constructed during August 2001 and replaced the traffic lights originally at this intersection ) and then continues northeast through a densely populated residential area. The highway leaves Mount Rainier and enters Brentwood, where the highway meets Maryland Route 208 (MD 208; 38th Street). US 1 passes through North Brentwood as a four-lane divided highway without parking through a mix of residences and commercial establishments. The median widens as the highway crosses Northwest Branch Anacostia River and enters the city of Hyattsville. The highway begins to closely parallel CSX Transportation's Capital Subdivision railroad line and MARC Train's Camden Line as it reduces to a four-lane undivided highway, passing the District Court of Maryland for Prince George's County building. US 1 curves to the north, and the highway's name changes to Baltimore Avenue at Farragut Street, shortly before intersecting US 1 Alternate (US 1 Alt.).

US 1 continues north through downtown Hyattsville, gaining a center turn lane before entering the town of Riverdale Park, where the highway intersects MD 410 (East–West Highway). The highway enters a densely populated residential area, passing between Riverdale Park to the east and the town of University Park to the west. Shortly after the highway enters the city of College Park on the east, US 1 intersects Queens Chapel Road at a five-way intersection with the town of University Park still on the west side. Only busses may enter Queens Chapel Road from US 1. The highway fully enters College Park and enters the commercial area that makes up the downtown of the college town, expanding to a four-lane divided highway. After the intersection with College Avenue and Regents Drive, US 1 passes through the campus of the University of Maryland, College Park, including the historic Rossborough Inn and Fraternity Row. The highway leaves the campus after intersecting Campus Drive, which is unsigned MD 431, and crossing Paint Branch.

US 1 continues through the northern part of College Park as a five-lane road with center turn lane, passing through a suburban commercial area. The highway intersects Greenbelt Road, which is unsigned MD 430, before meeting MD 193 (University Boulevard) at a partial interchange. All movements not provided in the interchange require using Greenbelt Road to connect between US 1 and MD 193. After intersecting Cherry Hill Road, US 1 becomes a divided highway and meets I-95/I-495 (Capital Beltway) at a partial cloverleaf interchange. North of the interchange, the highway expands to a six-lane divided highway, leaving the town of College Park and passing by businesses and through a swath of the Henry A. Wallace Beltsville Agricultural Research Center, including the U.S. National Agricultural Library.

At Sunnyside Avenue, the highway reduces to a five-lane road with center turn lane and passes through a suburban commercial area in the unincorporated town of Beltsville. The highway meets Rhode Island Avenue at an oblique intersection and MD 212A (Powder Mill Road) at a more orthogonal intersection. Past this, the road curves north and parallels CSX Transportation's Capital Subdivision. The highway passes between a commercial strip on the southbound side of the highway and an industrial area on the east side of the railroad tracks. US 1 leaves Beltsville after crossing Indian Creek. The highway temporarily expands to a four-lane divided highway before returning to a five-lane road, passing between an industrial area to the east and office parks to the west. The road comes to an intersection with the official eastern terminus of MD 212 (Ritz Way). After Muirkirk Meadows Drive, which leads to Muirkirk Road, US 1 reduces to a four-lane undivided highway, passes under the latter highway, and intersects the eastern terminus of MD 200 (Intercounty Connector) and the ICC Trail before it enters a forested area.

US 1 gradually veers away from the railroad tracks as it approaches Laurel, passing Maryland National Memorial Park before entering a suburban commercial area ahead of Contee Road, where the center turn lane returns. At Cypress Street, the southbound direction gains a third lane through the intersection with Cherry Lane, where the northbound direction gains a third lane. After passing Towne Centre at Laurel and Laurel Shopping Center, US 1 splits into a one-way pair. The three to four northbound lanes veer northeast as Second Street, while the three to four southbound lanes take the name Washington Boulevard. The one-way pair intersects Bowie Road, the old alignment of MD 197, before intersecting MD 198, which takes the form of a one-way pair, eastbound Gorman Avenue and westbound Talbott Avenue. US 1 continues through the city of Laurel, intersecting Main Street just west of Laurel station before leaving Laurel by crossing the Patuxent River into Howard County.

Howard County
Immediately after crossing the Patuxent River, both directions of US 1 pass entrances to Laurel Park. The highway continues through North Laurel, with the one-way pair coming together shortly before the intersection with Whiskey Bottom Road. US 1 continues north as a five-lane road with center turn lane, crossing Hammond Branch. As the highway passes through a commercial area in Savage, the road becomes a divided highway. After Gorman Road, the roadways temporarily diverge to cross the Little Patuxent River, then come together again at the full cloverleaf interchange with MD 32 (Patuxent Freeway). US 1 becomes undivided and intersects Guilford Road and crosses over the Columbia Branch from CSX Transportation's Capital Subdivision to the east. The highway passes several industrial parks, crossing Dorsey Run twice before intersecting MD 175 (Waterloo Road) in Jessup.

North of Jessup, US 1 crosses Deep Run and passes more industrial parks. The highway intersects MD 103 (Meadowridge Road) and passes Meadow Ridge Memorial Park before a partial cloverleaf interchange with MD 100 near Dorsey. Continuing northeast past Bealmear Branch, Old Washington Road splits to the northeast to pass through the center of Elkridge shortly before US 1 intersects the old alignment of MD 103, Montgomery Road. The highway passes through a shallow S-curve before receiving the other end of Old Washington Road and passes under the Capital Subdivision. US 1's two directions become divided by a Jersey barrier as the highway passes through the commercial strip in Elkridge, passing ramps to and from I-895 (Harbor Tunnel Thruway) immediately before crossing the upper Patapsco River into Baltimore County.

Baltimore City and County
After passing under I-895, US 1 intersects South Street, which provides access to St. Denis and Relay, and passes through its interchange with I-195 (Metropolitan Boulevard). The undivided highway crosses over CSX Transportation's Baltimore Terminal Subdivision railroad line before reaching the partial interchange with US 1 Alt. Washington Boulevard continues straight northeast as US 1 Alt. through Halethorpe, while US 1 exits onto Southwestern Boulevard to head north through Arbutus. The three-lane road with center turn lane and extra-wide shoulders parallels Amtrak's Northeast Corridor railroad line and MARC Train's Penn Line. After crossing Herbert Run, US 1 parallels the long, linear parking lot of Halethorpe station. The highway leaves the station after passing under Francis Avenue. US 1 expands to a five-lane road with center turn lane as it crosses under I-95. US 1 passes under Sulphur Spring Road and I-695 (Baltimore Beltway) as the highway heads out of Arbutus. The only connection with I-695 is a single ramp, exit 12A, from I-695 east to US 1 south. Inside the beltway, US 1 is paralleled by Leeds Avenue, which intersects the federal highway just before entering the city of Baltimore.

US 1 continues north as a four-lane divided street through a densely populated urban residential area. A short distance north of the city line, US 1 curves to the east onto Wilkens Avenue, which continues west as MD 372. The highway crosses Amtrak's Northeast Corridor and reduces to an undivided highway, intersecting US 1 Alt. (Caton Avenue) as it passes through a curve. US 1 crosses Gwynns Falls and CSX Transportation's Hanover Subdivision railroad line, expanding to a divided highway before passing the Deck of Cards rowhouses between Brunswick Street and Millington Avenue. A short distance to the east, US 1 turns north onto a one-way pair, Monroe Street southbound and Fulton Avenue northbound, to pass through a densely populated urban residential area on the west side of central Baltimore. US 1 meets the eastern terminus of MD 144 at another one-way pair, Pratt and Lombard streets. The highway passes over the US 40 freeway, which is accessed by the one-way pair adjacent to the freeway, Mulberry and Franklin streets. At Edmondson Avenue, Fulton Avenue becomes two-way; however, southbound US 1 remains on Monroe Street. Shortly after passing over Amtrak's Northeast Corridor, US 1 reaches North Avenue. The Fulton Avenue/Monroe Street one-way pair continues north as MD 140, while both directions of US 1 turn east onto North Avenue.

North Avenue heads east as a four-lane undivided highway through the junction with MD 129, which follows southbound Druid Hill Avenue and northbound McCulloh Street. US 1 continues east as a four-lane divided highway with parking lanes. The highway meets I-83 (Jones Falls Expressway) and Mount Royal Avenue next to North Avenue station of Maryland Transit Administration's Baltimore Light RailLink. US 1 expands to six lanes and crosses over the light rail tracks, Jones Falls, MD 25 (Falls Road), and CSX Transportation's Baltimore Terminal Subdivision. Due north of Downtown Baltimore, North Avenue intersects Charles Street (MD 139 to the north), St. Paul and Calvert streets (MD 2 to the south), and Greenmount Avenue (MD 45 to the north), after which North Avenue passes along the north side of Green Mount Cemetery. North Avenue reduces to a four-lane undivided street east of MD 45. Shortly after intersecting MD 147 (Harford Road) and Broadway, US 1 turns northeast onto Bel Air Road.

Now a four-lane undivided road, US 1 crosses the Baltimore Terminal Subdivision again and passes Clifton Park before reaching Erdman Avenue, which heads southeast as MD 151. The highway crosses Herring Run before intersecting Moravia Road, where Bel Air Road transitions from passing through densely populated residential neighborhoods to being the center of a commercial strip. US 1 intersects Frankford and Hamilton avenues before leaving the city of Baltimore at Fleetwood Avenue, which forms the eastbound component of a one-way pair with Northern Parkway at the latter street's eastern terminus. US 1 passes through the inner suburb of Overlea, crossing Stemmers Run before meeting I-695 (Baltimore Beltway) at a cloverleaf interchange.

US 1 continues northeast from the beltway as a six-lane divided highway. The highway intersects Rossville Boulevard and Putty Hill Road, then crosses MD 43 (White Marsh Boulevard). US 1 accesses MD 43 via two quadrant ramps with a right-in/right-out interchange southbound and an intersection with Dunfield Road northbound. North of MD 43, US 1 reduces to a four-lane undivided highway as it passes through Perry Hall, intersecting Silver Spring, Joppa, and Ebenezer roads in the midst of a commercial strip. After the intersection with Honeygo Boulevard, US 1 descends into a steep valley to cross Gunpowder Falls, passing southeast of a park-and-ride lot before the bridge. The highway continues north through a mix of farmland and residential subdivisions, heading through Kingsville before passing through Gunpowder Falls State Park and leaving Baltimore County by crossing Little Gunpowder Falls.

Harford and Cecil counties
US 1 heads northeast into Harford County, passing through a forested area and then the residential subdivisions of Pleasant Hills before reaching MD 152 (Mountain Road). The highway continues east through a commercial strip toward the hamlet of Benson, where US 1 converges with MD 147 (Harford Road) at an acute angle. US 1 Business (US 1 Bus.) heads east from the intersection toward Bel Air, while US 1 continues northeast on the Bel Air bypass. The bypass begins as a four-lane divided highway but drops to a two-lane road before crossing Winters Run. US 1 intersects Tollgate Road, gaining a lane northbound, before meeting MD 24 (Vietnam Veterans Memorial Highway) at a T intersection with sweeping right-turn ramps. MD 24 joins US 1 in a concurrency north on a four-lane undivided highway that passes under Vale Road. MD 24 leaves US 1 at a partial cloverleaf interchange with Rock Spring Road, which heads south as MD 924 toward downtown Bel Air. The bypass continues northeast with two lanes, its name changed to the Hickory Bypass before expanding to a four-lane divided highway and intersecting US 1 Bus. (Conowingo Road) south of Hickory. US 1 intersects the eastern end of MD 23 (East–West Highway) and MD 543 (Ady Road) before reducing to a two-lane road and receiving the northern end of US 1 Bus.

US 1 continues northeast as Conowingo Road through farmland. The old alignment of US 1, Forge Hill Road, splits to the east in Kalmia and rejoins the present highway 3 mi later after separate crossings of Deer Creek. The highway passes through a commercial strip around the intersection with MD 136 (Whiteford Road/Priestford Road) as US 1 passes to the south of Dublin. US 1 curves east at the intersection with MD 440 (Dublin Road). Smith Road, another old alignment of US 1, splits to the northeast as US 1 heads toward Darlington, where it meets MD 161 (Main Street) and MD 623 (Castleton Road). The highway passes a weigh station on the southbound side that serves both directions immediately after the MD 623 intersection and heads straight over a series of hills, gaining climbing lanes in either direction. At Shuresville Road, US 1 curves to the northeast and crosses the Susquehanna River on top of Conowingo Dam, a hydroelectric dam owned by Exelon, into Cecil County.

Immediately on the east side of the river, US 1 intersects the northern terminus of MD 222 (Susquehanna River Road) and passes over Norfolk Southern Railway's Port Road Branch. The highway gains a climbing lane northbound as it ascends a hill to Conowingo, where the highway meets the southern terminus of US 222 (Rock Springs Road). US 1 turns east and meets a pair of old alignments: Connelly Road heading northwest and MD 591 (Colora Road) heading southeast toward a removed bridge over Octoraro Creek. After US 1 crosses the creek, the old alignment reconnects with the mainline as another segment of MD 591, Porters Bridge Road. West of Rising Sun, MD 273 (Rising Sun Road) continues straight toward the town while US 1 curves northeast as the Rising Sun bypass. US 1 intersects the northern terminus of MD 276 (Jacob Tome Memorial Highway) and crosses Stone Run twice before turning north to the Pennsylvania state line. The highway continues across the state line toward Oxford, Pennsylvania, becoming a four-lane divided highway just across the state line.

Colonial and turnpike eras
The original predecessors of US 1 were a collection of dirt roads cut through the forests and farmland of central and northern Maryland in the 18th century. Construction of these roads was governed by a 1704 Act of the Province of Maryland requiring counties to oversee construction and build 20 ft roads to benefit transport of carts between population centers. The first segment of the road between Baltimore and Washington DC was built in 1741 between Baltimore and Elkridge (then known as Elkridge Landing) as a southward extension of a road between Baltimore and Hanover, Pennsylvania. Passage across the then wider and deeper upper Patapsco River at Elkridge Landing was provided by Norwood's Ferry. In 1749, the road was blazed to Georgetown on the Potomac River via Waterloo, Laurel, and Bladensburg. The highway north of Baltimore was a road constructed in the second half of the 18th century to connect the port of Baltimore with farms in Baltimore and Harford counties in Maryland and in Lancaster and Chester counties in Pennsylvania. From the docks in Baltimore, the road passed through Harry Dorsey Gough's plantation at the Perry Hall Mansion (whence it was called "Gough's Road" or "Perry Hall Road" during this stretch) and Kingsville on its way to Bel Air. The highway headed east from Bel Air to Churchville, then north to a crossing of the Susquehanna River at Conowingo. The road continued east to Rising Sun, then turned north toward Oxford, Pennsylvania, where the highway connected with roads to Philadelphia.

In the early 19th century, many of these dirt roads were reconstructed as turnpikes. The Washington Turnpike was chartered in 1796, but no road building ever occurred. It was not until the Washington and Baltimore Turnpike was chartered in 1812 that construction began along a 60 ft right-of-way between the corner of Pratt and Eutaw streets, then at the western city limits of Baltimore, southwest along the old dirt road to the District of Columbia boundary southwest of Bladensburg. In 1817, a timber toll bridge replaced Norwood's Ferry in Elkridge Landing. The Washington and Baltimore Turnpike had its chartered revoked in 1865 and the highway was turned over to the supervision of the counties. The toll bridge at Elkridge was sold to the counties in 1869.

By 1825, a turnpike existed from Baltimore northeast toward Bel Air. The Bel Air Turnpike was constructed from the Baltimore city line of 1818 at the corner of North Avenue and North Gay Street through Perry Hall and Kingsville to a junction with the Harford Turnpike at Benson in Harford County. From Benson, the Bel Air Turnpike of Harford County continued east to Main Street in Bel Air. North of Bel Air, what is now US 1 followed county highways to the Conowingo Bridge, which was first constructed around 1820.

Construction and reconstruction of State Road No. 1
By the beginning of the 20th century, county maintenance of the corridor that would become US 1 was becoming inadequate for the increasing amount of traffic using the roads and becoming unacceptable to advocates of better roads. As a result, the Maryland General Assembly passed the first state-aid road construction law in 1904, providing matching funds from the state to the counties to surface their major highways. As the most important corridor in the state, much of the state-aid money in the relevant counties went to the road from Baltimore to Washington DC. Feeling the work done by the counties with state funds was inadequate, in 1906, the general assembly further appropriated a total of $90,000 (equivalent to $ in )—$30,000 each in 1906, 1907, and 1908 (equivalent to $, $, and $ in )—toward reconstruction of the Baltimore–Washington Boulevard. The 30 mi road between the city limits of Washington DC and Baltimore was officially designated State Route No. 1. Another $174,000 (equivalent to $ in ) was appropriated by the state legislature in 1908. The 1908 act contained stipulations requiring a realignment of the road between Beltsville and Contee to eliminate two grade crossings of the Baltimore and Ohio Railroad as well as grade separations with the railroad at Elkridge and Mount Winans.

By 1910, the Baltimore–Washington Boulevard was paved from the District of Columbia boundary southwest of Bladensburg north to Beltsville, with small gaps at Northeast Branch south of Hyattsville and at Paint Branch in College Park; from Contee to Elkridge; and from Hammonds Ferry Road in Halethorpe to the Baltimore city line at Gwynns Falls. The general assembly appropriated another $120,000 (equivalent to $ in ) in 1910 for the newly formed two year old Maryland State Roads Commission (SRC) to complete the Baltimore–Washington Boulevard. By 1915, State Route No. 1 was completely paved with the addition of the highway on a new alignment between Beltsville and Contee, the filling of the gaps in College Park and Hyattsville, and construction between Elkridge and Halethorpe. The road was constructed a minimum of 14 ft in width with macadam, gravel, and concrete, with curves straightened and grades reduced. Concrete sections in Laurel, College Park, and Bladensburg were among the first concrete roads in Maryland when they were poured in 1912. Concrete girder bridges were built at Northeast Branch and the Anacostia River in Bladensburg. A concrete bridge was built over the Patapsco River at Elkridge to replace an earlier iron bridge. Due to heavy traffic and inadequate initial construction, many of the sections constructed in the first few years of state aid had to be later rebuilt.

The barrage of heavy military vehicles that traveled the Baltimore–Washington Boulevard during World War I, as well as the severe winter of 1917–1918, devastated the highway. As a result, in 1918 and 1919, the highway was reconstructed from end to end. Some sections of the highway were completely rebuilt with concrete, while, along 18 mi of the road, concrete shoulders, among the first applied in Maryland, were added to both widen and strengthen the road. By 1919, the entire length of the Baltimore–Washington Boulevard was a minimum width of 20 ft. The only significant realignment during this reconstruction was the straightening out of Dead Man's Curve 0.5 mi south of Elkridge.

Construction north of Baltimore
All of present-day US 1 north of Baltimore, with the exception of the road from east of Rising Sun to the Pennsylvania state line, was designated one of the original state roads by the SRC in 1909. By 1910, the highway was paved from Bel Air to Kalmia. In 1910, the SRC purchased the Bel Air Turnpike, the Bel Air Turnpike of Harford County, and Conowingo Bridge from their private operators. The SRC also paved its first section of the road from Oakwood to the crossing of Octoraro Creek that year. The road from Rising Sun to Sylmar Road was completed in 1911, along with Bel Air Road from the Baltimore city limits to Franklin Avenue. The paved section along Bel Air Road was extended northeast to Hamilton Avenue in 1912. That year also saw the first paving in Harford County from Kalmia to Deer Creek. The remainder of the highway in Harford County—from Little Gunpowder Falls to Bel Air and from Deer Creek to the Conowingo Bridge—was completed in 1913. Bel Air Road was finished in Baltimore County in 1914 and was paved from North Avenue to the Baltimore city limits, then just north of Erdman Avenue, in 1915. The highway was paved between the Conowingo Bridge and Oakwood in 1914. The state road was constructed along the alignment of the turnpikes without digression except for a relocation at Gunpowder Falls to reduce the grades on the hills. The final sections of what was to become US 1 were paved in Cecil County between 1917 and 1921, when the gap between Octoraro Creek and Rising Sun was filled and the Sylmar Road link from east of Rising Sun to the Pennsylvania state line was paved.

U.S. Route designation
When US 1 was designated in 1927, its route through Baltimore was the same as it is today except the federal highway entered the city from the southwest along Washington Boulevard. The highway turned north onto Monroe Street, which it followed to its present course north of Wilkens Avenue. This effectively replaced several auto trails that had been signed along the route. North of Baltimore, the road had been signed as the Baltimore PIke; south of there, it was part of a feeder route for the Lincoln Highway. South of Bel Air, the road was part of the Capitol Highway, connecting Washington DC to Philadelphia and Atlanta.

Reconstruction north of Baltimore
US 1's first major relocation north of Baltimore occurred at the Susquehanna River. The Conowingo Bridge was removed before it could be inundated by the Conowingo Reservoir set to fill upon the completion of Conowingo Dam in 1928. The old approaches, which consisted of Smith Road from near Darlington to Glen Cove on the west side of the river and Connelly Road, Ragan Road, and Old Conowingo Road to the mouth of Conowingo Creek on the east side of the river, were replaced with the present highway between Smith Road and Connelly Road. Smith Road was redesignated MD 162, while the eastern approach became a western extension of MD 273.

US 1 saw three realignments north of Baltimore in 1934. A 3 mi relocation near Kalmia included a new bridge over Deer Creek. The old highway, which featured 26 curves, was designated MD 590. Another relocation occurred between Conowingo and Rising Sun, featuring a new bridge over Octoraro Creek. The old highway was designated MD 591. East of Rising Sun, a 90-degree turn was bypassed at the intersection of Telegraph Road (now MD 273) and Sylmar Road by the construction of a sweeping curve to the northwest of the intersection. The bypassed portion of Sylmar Road was designated MD 592.

Bel Air Road was expanded started in 1933. US 1 was widened to 40 ft from the Baltimore city line northeast to Joppa Road. The highway was widened to 30 ft from Joppa Road to Bel Air. The 30 ft road was the first construction in Maryland of a three-lane road with center turn lane.

Baltimore–Washington Boulevard receives relief
Massive increases in traffic during the 1920s made the reconstruction of the late 1910s obsolete within the decade. Construction to expand the entire length of the Baltimore–Washington Boulevard with two 10 ft shoulders to 40 ft in width, allowing for four lanes, began in 1928. The final sections of the expanded highway, between the District of Columbia line and Bladensburg and a bypass to the west of Elkridge and over the upper Patapsco River, including the present underpass of the Baltimore and Ohio Railroad, were completed in 1931. The old colonial era Main Street through Elkridge was designated as MD 477. Despite the widening of US 1 between Baltimore and Washington DC in the late 1920s, the highway continued to be a major problem for both local and through traffic. The very high traffic levels made the highway a very attractive location for businesses serving travelers, leading to the sobriquet of "hot dog highway". The captive audience also led to the construction of over 1000 billboards between the two cities, spurring another nickname: "billboard boulevard". US 1 was also nicknamed "bloody Mary" due to the very high accident rate on the highway. After 1930, businesses were packed up to the edge of the four-lane, shoulder-less road that was largely built on an alignment poorly suited for the increasing speeds of vehicles. Thus, further expansion of the highway or safety improvements were impossible without expensive condemnation proceedings or relocating the highway. Businesses were adamantly against the latter solution.

In 1939, US 1's departure north from Washington Boulevard in Baltimore was moved south from Monroe Street to Caton Avenue just north of the city line. From Caton Avenue, US 1 followed Wilkens Avenue to Monroe Street. Caton and Wilkens avenues were expanded between 1936 and 1938, including removal of streetcar tracks and expansion to a divided boulevard on Wilkens Avenue, to handle the increased traffic as a "through-street". By 1946, a US 1 bypass was signed following Caton Avenue north from Wilkens Avenue, continuing on Hilton Street to North Avenue, then taking North Avenue east to rejoin US 1 at Monroe Street. Southwestern Boulevard was completed in 1950 as a dual highway through Arbutus, with grade separations with Sulphur Spring Road and Francis Avenue. US 1 was moved to its present alignment along that boulevard and Wilkens Avenue and old US 1 through Halethorpe was designated US 1 Alt.

During World War II, US 1 was relocated from Baltimore Avenue and Bladensburg Road between Washington DC and Hyattsville to Rhode Island Avenue, which was widened to 36 ft in 1940. Rhode Island Avenue between Mount Rainier and Hyattsville had originally been MD 411. The old US 1 south of Hyattsville became US 1 Alt. Despite these relocations and upgrades, true relief did not come until the first limited-access highway between Baltimore and Washington DC, the B–W Parkway, was completed in 1954 to remove long-distance traffic from US 1. With the completion of that highway and later the Baltimore Harbor Tunnel Thruway (I-895) in 1957 and, later, I-95, US 1 between the two cities became a highway mainly for local traffic.

Recent improvements
Dead Man's Curve was bypassed south of Elkridge in 1946. A bypass of Laurel was constructed around 1950. In 1952, northbound US 1 was placed on Fulton Avenue in West Baltimore opposite southbound US 1 on Monroe Street. North Avenue was widened to a divided highway for much of its US 1-designated length by 1957. By 1960, this bypass had become the northbound lanes of the present one-way pair. US 1 north of Baltimore was reconstructed to modify curves and widen the road in the 1950s. The highway was reconstructed in Cecil County from Conowingo Dam to Rising Sun in 1952 and 1953 and from Rising Sun to Sylmar in 1954. US 1 in Harford County was reconstructed from Little Gunpowder Falls to north of Deer Creek in 1952 and 1953 and to Conowingo Dam between 1954 and 1956. In Howard County, the highway was resurfaced from Elkridge to Waterloo in 1954 and from Waterloo to the Patuxent River in 1956. By 1958, US 1 was being widened from Laurel to Beltsville. The highway's bypass of Rising Sun was completed in 1957. MD 273 was extended west from Sylmar through Rising Sun along the old alignment to the southern end of the bypass. The Bel Air bypass was placed under construction in 1964 and completed in 1965, resulting in the designation of US 1 Bus. along the old road through Bel Air. The Bel Air bypass was extended north around Hickory in 2000, with US 1 Bus. extended to meet the northern end of the bypass.

<!-- History Notes

Maps: 1910-MGS: Paved from DC to Beltsville with short gaps south of Hyattsville and at Paint Branch Paved from Contee to Elkridge Paved from Halethorpe to city line at Gwynns Falls

1910: Planned on both present Alt 1 and Rhode Island Ave from DC to US 1-US 1 Alt junction in Hyattsville Paved from Hyattsville to railroad curve in Beltsville Planned from Beltsville to Contee Paved from Contee to Laurel Paved from Laurel to just south of Elkridge Planned from Elkridge to St. Denis ?Paved from St. Denis to near Francis Ave in Halethorpe Paved from Hammonds Ferry Road in Halethorpe to B&O RR crossing Planned from North Avenue NE out of Baltimore to Bel Air Paved from Bel Air to Deer Creek Planned from Deer Creek to near Rock Springs ?Paved from near Rock Springs to near Richardsmere Planned from there to Rising Sun Paved from Rising Sun to Sylmar; no highlighted road heading north into PA

1911: Paved from DC to Beltsville with gaps (planned) at the Peace Cross and between Campus Drive and Metzerott in College Park Under construction from Beltsville to just north of Contee Paved from just north of Contee to Bowie Road Planned from Bowie Road to Patuxent Paved from Patuxent to south Elkridge Planned from Elkridge to Monroe Ave Paved from Monroe to CSX RR Proposed from North Ave to city line (at Erdman Ave?) Paved from city line to 1 mi from city line Proposed from there to Bel Air Paved from Bel Air to Hickory State aid from Hickory to just west of Deer Creek Paved through Deer Creek Proposed from Deer Creek to near Dublin Under construction from Dublin to Susquehanna Proposed from Susquehanna to near Rock Springs Paved from Rock Springs to near Richardsmere Proposed from Richardsmere to Rising Sun Paved from Rising Sun to Sylmar Still no marking for exit to PA

1915: Complete everywhere except from DC to Hyattsville and from Richardsmere to Rising Sun and the exit to PA

1921: Complete everywhere, including exit to PA

1927: US 1 follows Washington Blvd to Monroe St, thence to North Ave then Bel Air Road. Fulton St is also paved. Crosses Susquehanna at Conowingo Bridge, with different approach roads.

1928: New approach roads built to Conowingo Dam from both sides

1934-1938: US 1 follows Washington Blvd to Monroe St

1935: Deer Creek Relocation shown; Half Mile Curve shown

1939: US 411 marked on Rhode Island Ave in DC; US 1 follows Alt 1 to Hyattsville, then current route north; 477 marked on old road through Elkridge, which has been bypassed; US 1 follows Caton Ave, Wilkens Ave, Monroe St, North Ave, and Bel Air Road through Baltimore; follows Half Mile Curve at turn from Rising Sun to Sylmar

1940: MD 411 marked on Rhode Island Ave; US 1 still on Bladensburg Road

1946: US 1 on Rhode Island Ave; In Baltimore, Bypass US 1 follows Caton Ave and Hilton St to North Ave, then east to main road

1948: US 1 on Rhode Island Ave

1949: Southwestern Blvd completed; marked as Alt US 1

1950: US 1 on Southwestern Blvd, which is marked as dual highway

1960: US 1 bypasses Rising Sun; US 1 follows Fulton/Monroe one-way pair; US 1 follows one-way pair in Laurel

1964: Bel Air Bypass under construction; includes proposed road past Hickory

1965: Bel Air Bypass complete to US 1 north of Bel Air; old US 1 east to 24 marked as 147; Hickory part still proposed

1966: no proposed bypass of Hickory; old road is US 1 Bus

SRC Reports:

1911: p. 7: Construction of State Road No. 1 provided for in Acts of 1906 and 1908 p. 8: State Aid Law of 1904 spurred demand for state-financed construction of a road from Baltimore to Washington; Acts of 1906 and 1908 provided 90k and 174k, respectively, for construction of Road 1. p. 15: An Act of 1910 allowed SRC to purchase Conowingo Bridge p. 17: Turnpikes purchased: Bel Air (15 mi); Turnpike at Bel Air (2.5 mi) p. 18: At end of 1911, 18.44 mi of Road 1 completed p. 22: Chart for B-W Road: 8.11/14.38 completed in PG, 10.02/10.88 completed in HoCo, 0.44/4.88 completed in Baltimore County, 0.31/0.42 completed in Baltimore City; 4.70 mi under construction in PG p. 25: Act of 1910 appropriated 120k to complete construction on B-W Road from Laurel to Beltsville and through Elkridge. Unfinished sections: DC-Hyattsville, Paint Branch, Laurel, and Baltimore County p. 30: Lists roads constructed 1908-1911: come back if the 1915 report does not make this redundant

1915: p. 50: Uncompleted Secondary Gaps: Octorora Creek-Rising Sun (4.25 mi) p. 52: Incorporated Towns Not Built Through Due to Lack of Funds: Rising Sun (0.60 mi) Incorporated Towns Having an Uncompleted Gap in the State Road System: Bel Air (0.70 mi) p. 58: State bridges constructed 1912-1915: Winters Run, Bel Air Road (1913), Little Gunpowder, Bel Air Road (1914), Anacostia River (1914), Eastern Run (1914), Patapsco River (1915) p. 68: Baltimore-Washington Boulevard section: section from Baltimore to Elkridge laid out in 1741; to both Washington and to Susquehanna River in 1749 p. 69: Baltimore-Washington Turnpike Company formed in 1812 and built a road 60 feet wide between the cities. Road taken over by state in 1865. Turned over to counties to maintain until 1906. In 1906, General Assembly appropriated 30k/year for 1906-1908 to construct portions of the highway as a state road known as State Road No. 1. Additional appropriations made in 1908, stipulating the road must run between Contee and Beltsville to avoid two RR crossings (Old Baltimore Pike). Road now complete for 29.95 mi between city limits of two cities (37.70 mi from Capitol to City Hall). Due to narrow road and heavy traffic, sections constructed in the few years prior to 1906 had to be reconstructed. p. 70: Grade crossings eliminated at Winans and Elkridge, in addition to the Contee-Beltsville relocation. p. 71: Elkridge bridge expected to be completed in 1916. p. 90: Relocation on Bel Air Road just south of Gunpowder Falls to reduce grades (0.7 mi) p. 110: Completed State Roads Cecil: Oakwood-Octoraro (1910, 3.10 mi); Rising Sun-near Mt. Sylmar Road (1911, 3.25); Conowingo-Oakwood (1914, 1.67) p. 112: Completed State Roads Harford: Kalmia-Deer Creek (1912, 2.22 mi); Little Gunpowder-Benson (1913, 2.85); Dublin-Susquehanna (1913, 4.24); Poole-Dublin (1913, 1.42); Benson-Bel Air (1913, 2.35); Deer Creek-Poole (1913, 0.91) p. 116: Completed State Roads Baltimore Co.: Bel Air Road: City Limits-Franklin Ave (1911, 1.95 mi); Franklin Ave-Hamilton Ave (resurfacing, 1912, 1.00); Kingsville-Harford Co. (1914, 2.14); Moores Run-Perry Hall (1914, 6.04); Moores Run-Kingsville (1914, 2.50) Baltimore City: Bel Air Road from North Ave to city limits (1915, 0.89) p. 132: State Road No. 1 Expenditures: (roads listed only) Baltimore City: Columbia Avenue (0.42 mi) Baltimore County: Patapsco River-B&O Overhead Crossing (0.80); B&O Crossing-Gwynns Falls (0.45); B&O Crossing-Morrell Park (1.15); Herberts Run-Winans (0.53); Windsor Ave-Lansdowne Road (1.84) Howard: Wesley Grove-Elkridge (2.78); Guilford X-Roads-Waterloo (2.33); Elkridge Relocation Patapsco River south (0.89); Through Elkridge (0.70); Patuxent River northward (0.53) PG: Main St Laurel-Crow Run (0.63); Berwyn to Paint Branch (0.36); Laurel-Beltsville (4.73); DC-Anacostia (0.95); Eastern Run-Eastern Run (0.47) p. 134: Reconstruction Expenditures: Bel Air Turnpike BaltCo (5.13); B&W Blvd HoCo (4.36); B&W Blvd PG (7.14)

1919: p. 34: 6.14 mi of concrete shoulders constructed between Laurel and Patapsco River, and 4.75 mi concrete roadway in 1917 and 1918 In PG, 10.4 mi concrete shoulders and 0.5 mi concrete roadway Dead Man's Curve at Elkridge straightened out p. 39: 2.03 mi of concrete shoulders built along highway in Balto County. p. 42-43: In Cecil County, 3.1 mi of roadway added: 1.5 between Porters Bridge and Rising Sun, 1.4 from Rising Sun to PA line at Sylmar, 0.3 on approach to Conowingo Bridge; 2.1 mi between Porters Bridge and Rising Sun under construction (contradictory?) to complete US 1 road. New bridge necessary at Conowingo Creek

1926: p. 39: 40-foot wide bridge under construction at Laurel

1930: p. 11: First building of State Road No. 1 finished by 1915. Rebuilt in 1918-1919 from end to end after it was torn up by World War traffic. Widened and rebuilt a third time since 1920. p. 68: Grade separations at Vinegar Hill in St. Denis, Relay (US 1?), and Hyattsville built in period of report p. 83: The outstanding project in the state is widening of Baltimore-Washington Blvd between Hyattsville and Baltimore by two 10-foot concrete shoulders to a total width of 40 feet.

1934: p. 30: Final links in 40-foot widening of Baltimore-Washington Blvd completed. Highway widened between 1928 and 1931. Final links were Bladensburg to DC and the bypass of Elkridge. p. 35: Projects begun by 1934: Bel Air Road: 40-foot road under construction from completed 40-foot section near Baltimore city line to Joppa Road. 30-foot road from Joppa Road to Bel Air. Work on project practically completed. Deer Creek Relocation: 3 mi relocation eliminating 26 curves on old road, with new bridge over Deer Creek built as part of this project (sounds completed; aerial picture of relocation on p. 36) Rising Sun Relocation: eliminates dangerous right-angle turn p. 37: Construction of a bridge and relocation at Porters Bridge (aerial on p. 38) p. 49: undergrade crossing of B&O RR at Elkridge (present crossing on US 1) (picture on p. 50)

1936: p. 54: Grade Crossing Eliminations: Wilkens Avenue, Washington Blvd at Winans p. 79: Bel Air Road projected started in 1933 completed in period of report p. 82: Relocations at Porters Bridge and Sylmar completed in period of report p. 99: In Baltimore City, considerable progress made on thru-traffic streets from Philadelphia Road to Washington Blvd and National Road. Wilkens Ave widened and repaved from Monroe St to Caton Ave; Caton Ave repaved from Wilkens Ave to Washington Blvd. Includes new bridges over Western Maryland Railway and Gwynns Falls on Wilkens Ave

1938: p. 141: Wilkens Ave streetcar tracks removed and divided boulevard built (two 27 ft lanes and 6 ft median) between Dukeland St to Bentalou St

1940: p. 111: Rhode Island Ave (1.2 mi) between Hyattsville and Mt. Rainier widened to 36 ft

1944: p. 4: B-W Blvd reconstruction in Baltimore and Howard counties approved for essential construction by War Production Board; construction began after period of this report

1946: p. 94: Dead Mans Curve at Elkridge bypassed by 0.511 mi relocation

1948: p. 66: Bridges designed July 1946 to June 1947: Sulphur Spring Road over Wilkens Avenue Extended, which is Southwestern Blvd p. 68: Bridges designed July 1947 to June 1948: Francis Ave and Sulphur Spring Road over Penna RR; Wilkens Ave Ext over Herbert Run; Bridge over Patuxent and Race Track Road for proposed bypass of Laurel. None of these structures were necessarily built. p. 120: Wilkens Ave Ext under construction from Penna RR bridge at Wilkens Ave to Winans on B-W Blvd p. 126: B-W Blvd widened through College Park; resurfaced from College Park to DC, including Rhode Island Ave

1950: p. 126: Bridges over Patuxent River and Race Track Road on Laurel Bypass and the bypass itself (1.555 mi, one lane concrete) completed 1950 p. 142: Francis Ave and Sulphur Spring Road bridges completed and Southwestern Blvd completed in 1950. US 1 resurfaced in Baltimore County in 1950

1952: p. 126: US 1 resurfaced, widened, and relocated between Conowingo Dam and Rising Sun (6.98 mi) started in 1952, completed in 1953 per 1954 p. 153 p. 156: US 1 widened and resurfaced from Broadway and Hickory toward Conowingo from Bel Air (5.38 mi) completed in 1952 US 1 resurfaced from 5.4 mi NE of Bel Air toward Conowingo (2.97 mi) started in 1952, completed in 1953 per 1954 p. 179

1954: p. 150: US 1 resurfaced, widened, and relocated from west limit of Rising Sun to MD 273 jct (2.17 mi) started in 1954 p. 174: US 1 has been reconstructed from Baltimore Co line to end of Deer Creek relocation (13.70 mi); remainder of US 1 to Conowingo is under contract p. 177: US 1 relocated, widened, and resurfaced in two sections (2.67 and 3.22) from Deer Creek relocation to Dublin (2.67) to Conowingo (3.22) p. 179: US 1 resurfaced from Balto Co line to MD 24 in 1952 p. 216: US 1 resurfaced from Levering Ave to MD 175; seven bridges widened through Howard County

1956: p. 137: Rising Sun Bypass under contract, expected to open summer 1957 p. 163: US 1 reconstruction finished from Deer Creek relocation to Conowingo Dam p. 205: US 1 resurfaced from MD 175 to Patuxent River

1958: p. 53: US 1 widened and resurfaced from Main St Laurel to R.I. Ave. Beltsville (6.61 mi) starting in 1956

History of Road Building in Maryland: p. 9: In second half of 18th century, road built to connect Baltimore with farms in Baltimore and Harford Counties and Lancaster and Chester counties in Pennsylvania. This road constructed from docks in Baltimore through Perry Hall and Kingsville to Bel Air, east to Churchville, northeast to Conowingo, east to Rising Sun, then went north toward Oxford, PA p. 36: By 1825, seven turnpikes entered Baltimore: two were Baltimore to Bel Air and Baltimore to Bladensburg and Washington p. 53: Among five experimental sections of concrete road built by SRC in summer 1912, three were on B-W Blvd in Laurel, Paint Branch, and Bladensburg p. 56-57 (centerfold): 1909 state road system includes B-W Blvd, Bel Air Road, and Conowingo Road to Rising Sun. Road to Sylmar not included p. 65-66: First concrete shoulders in Maryland laid on Bel Air Road and B-W Blvd to widen road and make it stronger to bear heavy military vehicles. Shoulders were added to 18 miles of B-W Blvd to increase width to 20 feet. Chapter VIII: Washington Boulevard: The Rise and Fall of Number One p. 75: First road paved by the state; known as State Road No. 1; in 1954, "hot dog highway" "billboard boulevard" and "bloody Mary" bypassed by Baltimore-Washington Expressway First section built to connect Baltimore to Elkridge, at which Norwood's Ferry crossed the Patapsco. In 1749, road continued south to Georgetown via Waterloo, Laurel, and Bladensburg. Constructed as a dirt road by the counties under the 1704 Act requiring cart roads 20 feet wide. p. 77: In 1820 a turnpike on 60 foot ROW built between the two cities p. 78: Norwood's Ferry replaced by timber toll bridge in 1817 (huh?) Turnpike condemned by state in 1865 for disrepair and turned over to counties; Elkridge toll bridge sold to counties in 1869 p. 79: In 1906, state appropriated $90k to reconstruct what was designated State Road No. 1 for 30 miles between Baltimore and DC. Road was built to 14-foot width of macadam, gravel, and concrete. Grades reduced, curves straightened, 4 of 7 railroad grade crossings eliminated. Concrete bridge built to replace iron bridge at Elkridge; Concrete girder bridges built at Eastern Branch and over Anacostia Businesses sprung up to serve travelers along "hot dog highway" p. 80: WWI traffic and severe winter of 1917-18 destroyed highway; many sections completely built with concrete; all sections widened to at least 20 feet. Dead Man's Curve 1/2 mi south of Elkridge relocated around in 1919. p. 81: From 1928 to 1930, road widened to 40 feet (four lanes undivided); no further expansion was possible in most places without expensive condemnation because businesses were right up to the road. Billboard Boulevard had 1099 billboards (39/mile) p. 85: Third road to supplement US 1 and B-W Expwy being planned by 1958 p. 106: Three-lane road constructed between Joppa Road and Bel Air

The Turnpikes of Maryland (DAR): p. 571: Charter for Washington and Baltimore Turnpike gave franchise to build from Baltimore to DC via Norwood's Ferry on the Patapsco, McCoy's Tavern, Vansville, White House, Ross Tavern, and Bladensburg. p. 572: passed out of Baltimore as Columbia Avenue, enters DC on Bladensburg Road

Maryland Geological Survey, Volume 3 p. 131: Baltimore-Elkridge Road was a branch or extension of a road between Hanover and Baltimore via Reisterstown completed in 1741 p. 166: first turnpike company chartered in Maryland in 1796 to build turnpike between Baltimore and Washington; nothing was built p. 172: Charter for Washington and Baltimore Turnpike in 1812 gave franchise to build from Baltimore to DC via Norwood's Ferry on the Patapsco, McCoy's Tavern, Vansville, White House, Ross Tavern, and Bladensburg. p. 176: By 1825, seven turnpikes entered Baltimore: two were Baltimore to Bel Air and Baltimore to Bladensburg and Washington p. 218: List of turnpikes extant in 1898 in Baltimore County: Bel Air Turnpike: Baltimore to Harford Co line p. 224-225 (between): map of Cecil County shows road from Conowingo to Rising Sun is a major county road; no road marked to Sylmar p. 236-237 (between): map of Harford County shows road from Bel Air to Hickory to Dublin to Conowingo is a major county road p. 237: List of turnpikes in Harford County: Bel Air Turnpike: from Harford Turnpike (at Benson) east 2.5 mi to Bel Air. p. 261: List of turnpikes in Maryland: Baltimore and Jerusalem Turnpike (16 mi); Bel Air Turnpike of Harford County (2.5 mi)

Bridges: US 1 proper: Conowingo Dam: 1927-1984 I-83 over North Avenue: 1959 North Avenue over Jones Falls, Falls Road, and RR: 1978 I-695 IL Arbutus over US 1/Amtrak: 1957 I-695 OL Arbutus over US 1/Amtrak: 2003 Francis Avenue over US 1/Amtrak I-95 NB and SB over US 1/Amtrak: 1970 US 1 over Gunpowder Falls: 1991 US 1 over Beltway: 1963-1971 US 1 over Patapsco: 1915-1952 US 1 over MD 24: 1964 I-195 EB and WB over US 1: 1987 All four MD 32 bridges over US 1: 1983 Fulton Avenue over I-170: 1975 Vale Road over US 1: 1963 US 1 NB over Patuxent: 1949-2006 US 1 SB over Patuxent: 1970 US 1 NB over Little Patuxent: 1955 US 1 SB over Little Patuxent: 1929 Octoraro Creek: 1933 US 1 over I-695 Overlea: 1995 US 1 over MD 43: 1993 Monroe Street over Amtrak/CSX: 1986 US 1 over MD 100: 1994 US 1 over Paint Branch: 1980 US 1 over CSX Columbia Branch: 1969 US 1 over Deer Creek: 1934-1993 US 1 over Winters Run: 1963 US 1 over Stemmers Run: 1960 US 1 over MD 193: 1988 Wilkens Avenue over Gwynns Falls: 1936 Washington Blvd over CSX: 1979 US 1 over CSX southwest Baltimore: 1930 Wilkens Avenue over Amtrak: 1928-1986 US 1 over Tollgate Road: 1963 US 1 SB over Northwest Branch: 1969 US 1 NB over Northwest Branch: 1956 US 1 over Sulphur Spring Road: 1947-1978 US 1 over Little Gunpowder Falls: 1934 US 1 over Herbert Run: 1949 US 1 over Norfolk Southern E of Conowingo Dam: 1931-1984 US 1 over Herring Run: 1925 US 1 over Bear Branch Laurel: 1985-2001 US 1 (NB) over Race Track Road: 1949 Wilkens Avenue over CSX: 1937 US 1 over Bealmear Branch (HoCo): 1929-1955 US 1 over Dorsey Run: 1929-1945 US 1 over Stone Run Rising Sun: 1956 US 1 over Whitemarsh Run: 1971 US 1 over Guilford Branch (HoCo): 1983 US 1 over Hammond Branch: 1929-1954 US 1 over Branch of Octoraro Creek (S of creek): 1931-1951 Fulton Avenue over Amtrak: 1936 US 1 over Deep Run: 1929-1955 US 1 over Indian Creek: 1975 US 1 over Branch of Stone Run Rising Sun: 1956 US 1 over Crones Run (HoCo): 1929-1955 I-895 over US 1: 1973

US 1 Bus Bel Air: US 1 Bus over Winters Run: 1930 US 1 Bus over Bynum Run: 1953

US 1 Alt Bladensburg: US 1 Alt over Anacostia: 1955 US 1 Alt SB and NB over Northeast Branch in Bladensburg: 1955-1998 US 1 Alt over CSX in Hyattsville: 1989 US 1 Alt over Branch of Northeast Branch: 1955

US 1 Alt Arbutus: US 1 Alt over I-695: 1957-1983 Caton Ave over I-95: 1971 US 1 Alt over US 1/Amtrak: 1936-1980

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