Kentucky Route 80

Kentucky Route 80 (KY 80) is a 483.55 mi state highway in the southern part of the U.S. state of Kentucky. The route originates on the state's western border at Columbus in Hickman County and stretches across the southern portion of the state, terminating southeast of Elkhorn City on the Virginia state line. It is the longest Kentucky State Highway, though the official distance as listed in route logs is much less due to multiple concurrencies with U.S. Route 68 (US 68) and US 23.

The route was split into two segments from 2003 to November 2009. Construction and relocation of KY 80 in Graves, Calloway, and Marshall counties during this time caused the route to be split. A new, four-laned 8.5 mi section of KY 80 opened in Calloway County on November 25, 2009. The route is now a four-lane divided highway from Mayfield to Bowling Green after the widening to four lanes from Canton to Cadiz was completed in 2020.

Jackson Purchase region
From Columbus, the road passes through Hickman, Carlisle, and Graves counties to Mayfield. Before 2003, the road passed through Mayfield and into Marshall County before converging with US 68 in Aurora. The two-lane segment of former KY 80 from Mayfield to Aurora now has two separate designations. From Mayfield to Brewers in Marshall County, the road retains its former co-designation as KY 58. The segment from Brewers to Aurora is now designated as KY 402.

From Mayfield, KY 80 travels along a new four-lane corridor into Calloway County and on to Murray. The route continues through eastern Calloway County and into Marshall County before converging with US 68 near the eastern terminus of KY 402 in Aurora.

Concurrency with U.S. 68
From Aurora, it follows US 68 through Trigg County, and dissects the Land Between the Lakes National Recreation Area. The two routes then makes its way through Christian, Todd, and Logan counties to Bowling Green (Warren County).

From Bowling Green through Glasgow to Edmonton, Kentucky Route 80 remains overlapped with US 68 serving eastern Warren, Barren and Metcalfe Counties until it goes a little past downtown Edmonton. KY 80 is part of the Kentucky Scenic Byways system for its entire concurrency with US 68.

Glasgow to Somerset
From Glasgow to Somerset, KY 80 is paralleled (and largely supplanted) by the Louie B. Nunn Cumberland Parkway, which is officially designated as the future route of Interstate 66 (I-66), although interest in that project has been lost.

KY 80 serves rural portions of Barren, Metcalfe, Adair (including Columbia), Russell (including Russell Springs), and southern Casey counties to Somerset, in Pulaski County.

Somerset to Hazard
Between Somerset and London (Laurel County), KY 80 is again the primary route. From London to Hazard, KY 80 is again supplanted, this time by the Hal Rogers Parkway (formerly the Daniel Boone Parkway), a Super-two highway that acts as an expressway in the area. KY 80 serves rural portions of Clay, Leslie, and Perry counties, including the city of Manchester, before rejoining the Parkway near Hazard.

Hazard to Pikeville and the Virginia border
KY 80 is a modern four-lane highway (though not controlled access) from Hazard through Knott County to Watergap in Floyd County where it converges with US 23. This section of Kentucky Route 80 was completely new construction; most of the remnants of KY 80's old alignment were renamed with several designations, primarily KY 550. KY 80 continues, concurrent with US 460 until reaching Belcher in Pike County and continues into Virginia from Elkhorn City as Virginia State Route 80.

Before 1980
KY 80's original western terminus was located near Bristow, just east of Bowling Green from its 1929 establishment through the early 1950s; the segment from Columbus to US 68 in Aurora was originally signed as KY 98. In the late 1940s, when US 68 was rerouted to its current routing between Bowling Green and Perryville, KY 80's western terminus was truncated to its junction with US 68 in Edmonton. KY 80 was extended to its late-20th century length, including the concurrency with US 68, at sometime in 1954. From around 1948 through 1953, Russell S. Dyche, an editor for the London Sentinel-Echo, led a years-long effort to persuade the Kentucky Department of Highways (now the Kentucky Transportation Cabinet) to extend the KY 80 designation westward onto its route from Edmonton to Columbus, including the US 68 concurrency. Dyche, who also led a motorcade to KY 80's current western terminus all the way from Elkhorn City, continued to promote the highway until his late 1959 death. In 1978, the segment of KY 80 from Somerset to London was named the Russell Dyche Memorial Highway.

Columbus-Belmont ferry
Originally, KY 80 continued westward via a ferry crossing of the Mississippi River to Belmont, Missouri, where it continued westward as Missouri Route 80, which travels west to US 61/US 62 (and I-55 in the present day) between New Madrid and Sikeston, Missouri. The toll ferry service was discontinued in 1984.

Proposed Interstate 66 in the Daniel Boone National Forest
The state's I-66 proposals called for KY 80 to be bypassed in the area between Somerset and London, with the new road to share only the crossing over the Rockcastle River gorge. This proposal has met with controversy in the mid-2000s, with area residents preferring that the new Interstate be built on the existing KY 80 right of way. The project has since lost interest.

Late 20th century realignments
KY 80's original alignments in Knott and Perry counties were renumbered to KY 550 at some point around 1979–1980. Several other segments of KY 80 were rerouted in various areas between Somerset and Prestonsburg between 1977 and 1984.

When the US 68/KY 80 four-lane realignment between Hopkinsville and Bowling Green was completed in the late 1990s, several of the route's old alignments were kept intact, notably in areas between Hopkinsville and Bowling Green. Old alignments of US 68/KY 80 in Fairview, Elkton, Russellville, Auburn, Bowling Green and Glasgow were converted into business routes of US 68. Sometime in 2007, the route was rerouted onto a bypass route around Cadiz; the original alignment in that city also became a US 68 business loop.

Rerouting in the Purchase area
The KY 80 alignment from Brewers to Aurora was renumbered as KY 402 at some point during the 2002/2003 fiscal year. Around that time, KY 80 was re-routed onto a four-lane highway from Mayfield to Aurora via the northern outskirts of Murray. The segment from US 641 to US 68 was completed in 2006, while the remainder was built during the 2008/2009 fiscal year.

Eggners Ferry Bridge collapse of 2012
On January 26, 2012, the Eggner's Ferry Bridge carrying KY 80 and US 68 over Kentucky Lake (Tennessee River) near Aurora collapsed because a cargo ship crashed into one of the bridge's support pillars. The bridge re-opened to traffic in May 2012, but it was replaced by a four-lane bridge that was built more than three years afterwards. A new bridge with similar design over Lake Barkley was completed in 2018 to replace the old bridge near Canton.

Mayfield business route
Kentucky Route 80 Business (KY 80 Bus.) is a business spur of KY 80 located in Mayfield, in Graves County. The main alignment of KY 80 was rerouted around Mayfield on a new four-lane alignment. Previously, KY 80 had 2.199 mi gap within the city from the Purchase Parkway (now-Interstate 69) interchange to US 45 in downtown Mayfield. KY 80's main alignment resumed beyond the US 45 junction.

Pulaski County connector route
Kentucky Route 80 Connector (KY 80 Conn.) is a roadway in Pulaski County that connects KY 80 with KY 3261. It is located on the west side of Somerset just outside of the city limits.

Somerset business route
Kentucky Route 80 Business (KY 80 Bus.) is a business route of KY 80 located in Somerset, the Pulaski County seat. It begins on the west side of Somerset at KY 80's junction with the KY 914 bypass. It intersects US 27 and KY 1247 in downtown. Its eastern terminus after intersecting KY 192 is at mile point 21.161 of the main route of KY 80 on the east side of Somerset.

Floyd County spur route
Kentucky Route 80 Spur (KY 80S) is a spur route of KY 80 in southern Floyd County. It connects KY 80 with KY 1428 at Martin.