U.S. Route 25E

U.S. Route 25E (US 25E) is the eastern branch of US 25 from Newport, Tennessee, where US 25 splits into US 25E and US 25W, to North Corbin, Kentucky, where the two highways rejoin. The highway, however, continues as US 25E for roughly two miles (3.2 km) until it joins Interstate 75 (I-75) in the Laurel County community of North Corbin at exit 29. The highway serves the Appalachia regions of Kentucky's Cumberland Plateau and the Ridge-and-Valley section of East Tennessee, including the urbanized areas of Corbin and Middlesboro in Kentucky and Morristown in Tennessee.

US 25E follows the original pathway of early U.S. pioneer Daniel Boone's Wilderness Road, which contributed to the increased settlement of Appalachia given its access through the rugged Cumberland Gap. By 1815, the route became the first state-funded road in Tennessee and, in 1923, unsigned State Route 32 (SR 32) in the Tennessee State Route System in its statewide entirety. It would be recognized as part of the Dixie Highway, one of the earliest federal auto trails, in 1915. The route was officially established as US 25E with the creation of the U.S. Numbered Highway System in 1926.

By 1965, economic conditions in Appalachia remained dire, and the formation of the Appalachian Regional Commission (ARC) provided new incentive for US 25E as part of the Appalachian Development Highway System (ADHS), designated as Corridor S in Tennessee and partially as Corridor F in both Tennessee and Kentucky. Corridor S follows US 25E between I-81 in Morristown to SR 63 (Corridor F) in Harrogate, and Corridor F follows the route from SR 63 to US 119 in Pineville. With its role in the ADHS, US 25E was planned for improvements as a regional limited-access highway between I-75 and I-81.

Initial construction work began in both states around the 1960s and 1970s but was accelerated in the 1980s and 1990s with additional federal funding for the section of US 25E between I-75 and I-81 with its designation as a federal truck route in the Federal Highway Administration (FHWA)'s National Network by 1982 and as High-Priority Corridor 12 of the National Highway System by Congress in 1991 with the passing of the Intermodal Surface Transportation Efficiency Act (ITSEA). In 1996, the highway received national recognition with its realignment under the Cumberland Gap with the large-scale Cumberland Gap Tunnel project. Considered a civil engineering achievement, the tunnel is one of two in the entire U.S. that crosses state lines.

US 25E serves as an arterial expressway for long-distance travelers and truckers connecting central Appalachia to the Great Lakes and Eastern Seaboard regions of the U.S. via access to I-75, I-81, and proximity to I-26 and I-40. Since the completion of the Cumberland Gap Tunnel in 1996, upgrades to freeway-grade standards have been planned and constructed for US 25E in both states to improve regional freight movement.

In 2009, all of US 25E in Tennessee, along with US 25 from Newport to the North Carolina state line, was designated as the East Tennessee Crossing Byway, a National Scenic Byway.