U.S. Route 21

U.S. Route 21 or U.S. Highway 21 (US 21) is a north–south United States Numbered Highway, spanning 393 mi from Hunting Island State Park, South Carolina, to Wytheville, Virginia. The route traverses three states, South Carolina, North Carolina, and Virginia. It connects southeastern cities, including Columbia, South Carolina, and Charlotte, North Carolina.

US 21 starts at Hunting Island State Park, bypasses Beaufort, South Carolina, and then heads north across the low country, paralleling Interstate 77 (I-77) through urban and rural areas before entering North Carolina. In North Carolina, US 21 frequently merges with and splits from I-77. The route enters Virginia, passing through hilly terrain before ending at the intersection of Interstate 81 (I-81) / U.S. Route 52 (US 52) in Wytheville.

Despite the "1" indicating that it is a major north–south highway, US 21 only travels through three states and is no longer a cross-country route, as many sections have been replaced by I-77 in Ohio and West Virginia. Historically, US 21 was longer before the Interstate Highway System was established. US 21 originally ran from Cleveland, Ohio, to Yemassee, South Carolina, it was later extended to Beaufort and Hunting Island State Park. Over time, its length was reduced, making it the second-shortest major north–south route after U.S. Route 91 (US 91).

US 21 serves as an alternative to the more heavily trafficked interstates in the area, particularly I-77, I-26, and Interstate 95 (I-95).

Route description

 * SC
 * 233 mi
 * NC
 * 125 mi
 * VA
 * 35 mi
 * Total
 * 393 mi
 * }
 * Total
 * 393 mi
 * }
 * }

South Carolina
US 21 travels 233.2 mi through the state. Beginning at Hunting Island State Park, US 21 travels west toward Beaufort, where it widens to four lanes. The route bypasses Beaufort to the south, going through Port Royal, Shell Point, and Burton. In the Beaufort area, US 21 passes by the entrances to Parris Island and Marine Corps Air Station Beaufort, the major Marine Corps installations in the area. North of Beaufort, US 21 continues as a four-lane divided highway and intersects with US 17. The route travels in a wrong-way concurrency with US 17 south for 7 mi before turning north toward Yemassee, where it becomes a rural two-lane road and intersects with US 17 Alternate. North of Yemassee, US 21 splits off and crosses I-95 at exit 42.

The two-lane route continues through rural portions of the state. US 21 goes through Smoaks and Branchville and bypasses Orangeburg. North of Orangeburg, US 21 runs roughly parallel to I-26 until Gaston where it conjoins US 321 and becomes an urban highway. US 21 passes through Cayce, West Columbia, and Columbia.

North of Columbia, US 21 splits from US 321, reverting to a rural two-lane road parallel to I-77. In York County, US 21 enters urban areas again, connecting Rock Hill and Fort Mill. Near the North Carolina state line, US 21 merges with I-77 near Carowinds, then enters North Carolina.

North Carolina
US 21 begins as a concurrency with I-77 in Charlotte, which it repeats three times within the state. Its first break with I-77 is along Statesville Avenue, then proceeding through Huntersville and Cornelius, however, because of its close proximity to I-77 and North Carolina Highway 115 (NC 115), it has no interchange with I-485 by itself. The second break with I-77 occurs at Mooresville, where US 21 travels through the city and then northwest into Statesville. After Statesville, US 21 travels northeast to Harmony and Brooks Crossroads, before merging back with I-77 near Jonesville. However, Jonesville and Elkin connect with US 21 Bus. through centers of both towns, as an alternate route paralleling I-77. North of Elkin, US 21 splits with I-77 for the last time and goes north to Sparta, passing the Blue Ridge Parkway after a major, curvy section. North of Sparta, at Twin Oaks, US 221 overlaps with US 21 before entering Virginia. US 21 travels 124.5 mi through the western Piedmont of North Carolina, either combined with I-77 or as a two-lane rural road; from the South Carolina state line to Elkin, travelers can easily skip a majority of US 21 via I-77.

Virginia
After a few miles crossing the state line, US 21 reaches the town of Independence, where it splits with US 221 and continues north. The route goes through the Mount Rogers National Recreation Area before entering the city of Wytheville. After a short concurrency with US 11 in downtown Wytheville, it goes north and ends at the intersection of I-81/US 52. US 21 travels 35 mi through western Virginia, mostly as a two-lane rural mountain road.

History
US 21 in the pre-Interstate era was a north–south highway connecting the area around Lake Erie and the coastal South. One of the few true north–south routes to cross the middle Appalachian Mountains, it became an important corridor for motor traffic between northeastern Ohio, western Pennsylvania, (with US 19) and western New York with central North Carolina, central and southeastern South Carolina, and (by connecting with other highways) coastal Georgia and most of Florida. Many referred to the stretch of US 21 from the Great Lakes Region to Florida as "The Lakes-to-Florida Highway".

US 21 originally (in 1926) connected Cleveland, Ohio, and Yemassee, South Carolina. In 1935 it was extended to Beaufort, South Carolina, and again in 1953 to its current southern terminus at the Atlantic Coast at Hunting Island State Park, between the city of Beaufort and Fripp Island.

In the Interstate Highway era, much of US 21 became an obvious corridor for a long-distance expressway. The West Virginia Turnpike between Charleston, West Virginia, and Princeton, West Virginia, was the first segment of a planned series of toll highways along or near US 21 from Cleveland to Charlotte, North Carolina. All the other toll highways were shelved in favor of freeways built with Interstate funding; these freeways and the West Virginia Turnpike became I-77, which completely supplanted old US 21 as a long-distance through route. I-77 was later extended to Columbia, South Carolina, also within a few miles of US 21.

Between Cleveland and Charleston, all but a relatively short segment of US 21 was completely deleted in favor of I-77, the relics being as follows:

Between Charleston and its current northern terminus at Wytheville, Virginia, almost all of US 21 ran concurrently with either US 60, US 19, or US 52, which remained as US 21 was deleted. The short segment of US 21 in southern West Virginia not coinciding with another U.S. Highway became an extension of West Virginia Route 16.
 * State Route 21 (SR 21) between Cuyahoga Heights and Strasburg;
 * SR 821 between I-77 near Byesville and SR 60 near Marietta, Ohio;
 * County Road 35 (CR 35, Oakwood Road, Byesville Road, Old Twenty-One Road) between Byesville and the Guernsey–Tuscarawas county line;
 * CR 3 (Salt Fork Road) between the Guernsey–Tuscarawas county line to SR 258
 * CR 21 between Newcomerstown and New Philadelphia
 * County Route 21 (CR 21) between Mineral Wells and Charleston.

In North Carolina, US 21 originally entered the state along today's NC 51 into Pineville, then followed Old Pineville Road into Charlotte. In the mid-1930s, US 21 moved over to South Boulevard from Old Pineville Road. In 1969, US 21 was rerouted following today's I-77 alignment, the old route was replaced by an extension of US 521. From 1975–1987, US 21 moved north in segments onto I-77 to its current alignment ending at exit 16A (Sunset Road). Further north, US 21 originally followed Old Statesville Road, replaced in 1956 by NC 115. In 1966, US 21 was bypassed around Jonesville and Elkin, replaced with US 21 Bus.

US 21 in Beaufort, South Carolina, was rerouted around the city over former SC 280 as well as a portion of SC 802. The new routing went into effect on February 26, 2012.

Special routes and auxiliary routes
There are currently four business loops, four connectors, and one truck route along its route. Auxiliary routes of US 21:
 * U.S. Route 21 Business (Beaufort, South Carolina)
 * U.S. Route 21 Business (Orangeburg, South Carolina)
 * U.S. Route 21 Connector (Orangeburg, South Carolina)
 * U.S. Route 21 Connector (West Columbia, South Carolina)
 * U.S. Route 21 Connector (Columbia, South Carolina)
 * U.S. Route 21 Connector (Ridgeway, South Carolina)
 * U.S. Route 21 Business (Fort Mill, South Carolina)
 * U.S. Route 21 Business (Elkin, North Carolina)
 * U.S. Route 21 Truck (Sparta, North Carolina)


 * U.S. Route 121
 * U.S. Route 221
 * U.S. Route 321
 * U.S. Route 421
 * U.S. Route 521