U.S. Route 23 (US 23) is a part of the United States Numbered Highway System that travels from Jacksonville, Florida, to Mackinaw City, Michigan. In the U.S. state of Tennessee, the highway travels in the northeastern part of the state from the North Carolina state line at Sam's Gap in the Bald Mountains to the Virginia state line in Kingsport. The entire route in Tennessee is a four-lane controlled-access highway and is concurrent with Interstate 26 (I-26) for most of its length. The freeway is also designated James H. Quillen Parkway for its entire length in Tennessee. US 23 in Tennessee is part of Corridor B of the Appalachian Development Highway System (ADHS) and serves as a major thoroughfare in the Tri-Cities region of the state. Although I-26 is technically an east–west route, the road predominantly travels in a north–south alignment in Tennessee. The highway reaches a maximum elevation of at the North Carolina state line, which is the highest elevation on the Interstate Highway System east of the Mississippi River.
US 23 was first established in Tennessee in 1930 following State Route 36 (SR 36), and paving of the route was completed the following year. The freeway was first authorized by the Appalachian Regional Development Act of 1965, and the stretch between Johnson City and the Virginia state line was constructed in segments between 1968 and 1986. In addition to US 23, this freeway was designated as State Route 137 (SR 137) and later Interstate 181 (I-181) and was commonly referred to as "Appalachian Highway" in its early years. In 1988, the American Association of State Highway and Transportation Officials (AASHTO) approved an extension of I-26 from Asheville, North Carolina, to I-81 in Tennessee. The remainder of the freeway was completed in 1995, and the stretch between the North Carolina state line and I-81 was redesignated as I-26 in 2003. After an initial denial, I-26 was extended north to Kingsport in 2007, replacing the remainder of I-181. Today, the mountainous stretch near the North Carolina state line is widely considered to be one of the most scenic stretches of Interstate Highway in the Eastern U.S.
Route description
US 23 and I-26 are maintained by the Tennessee Department of Transportation (TDOT), along with all other Interstate, U.S., and state highways in Tennessee. In 2025, annual average daily traffic (AADT) volumes ranged from 67,272 vehicles per day between SR 381 and SR 354 north of Johnson City to 10,731 vehicles per day at the North Carolina state line, which is the lowest traffic volume on any mainline Interstate Highway in Tennessee.
US 23 and I-26 enter Tennessee in Unicoi County from North Carolina at an elevation of at Sam's Gap in the Bald Mountains, part of the Blue Ridge Mountains. This is the highest elevation on the Interstate Highway System east of the Mississippi River and is near the Appalachian Trail crossing. A large truck parking area is located here off the northbound lanes. The freeway immediately begins a steep descent with a 6% grade, and trucks are advised to slow to between , depending on their weight. Along this stretch, mesh nets are placed next to artificial rock cuts to mitigate the effects of rockslides. A scenic overlook is located off the southbound lanes about beyond the state line, and less than beyond this overlook is a runaway truck ramp in the northbound lanes. The highway continues descending and crosses several long bridges over steep valleys that also serve as wildlife underpasses. The northbound lanes then have a second runaway truck ramp near where the elevation drops below . The freeway then rounds a relatively sharp curve and has its first interchange near the Flag Pond community. Turning northeast, the roadway continues to descend, with the grade gradually decreasing, and a northbound scenic overlook is provided a few miles later. The southern welcome center is located off the interchange with Clear Branch Road. Continuing its descent, the highway crosses additional valleys and drops below before beginning a concurrency with US 19W at an interchange in the Temple Hill community. The route then gradually levels out at the bottom of a deep mountain valley and reaches Erwin a couple of miles later.
Upon entering Erwin, US 19W/US 23/I-26 crosses the Nolichucky River. The freeway reaches the southern terminus of SR 81 and SR 107, the former of which also provides access to Jonesborough. It then leaves Erwin a few miles later and, gradually ascending a few hundred feet over the next few miles, enters the town of Unicoi, where it has an interchange with the western terminus of SR 173. Continuing through the same valley, the freeway gradually shifts into a more north–south alignment and briefly enters Carter County. An interchange is located at SR 359 where the highway enters Johnson City. The freeway zigzags over the next few miles before shifting mostly into a northwest-to-southeast alignment, crossing into Washington County, and entering the Ridge-and-Valley Appalachians. The roadway crosses a long viaduct over a railroad and several surface streets before reaching an interchange with US 321/SR 67, which connects to Elizabethton. Passing through the business district of Johnson City, the freeway has interchanges with multiple surface streets, including SR 91 and SR 400, and crosses multiple railroads and surface streets. The highway then proceeds through residential neighborhoods in the northern part of Johnson City and turns more northeastward before reaching a three-loop partial cloverleaf interchange with US 11E (North Roan Street), where US 19W splits off. Less than later is an interchange with SR 381 (State of Franklin Road). The freeway crosses a ridge before reaching SR 354 (Boones Creek Road), which provides access to nearby Jonesborough. Leaving Johnson City, the highway crosses additional ridges and proceeds through a mix of farmland and residential neighborhoods before reaching an interchange with SR 75 (Bobby Hicks Drive/Suncrest Drive) in the Gray community. The freeway passes through additional farmland and neighborhoods before crossing into Sullivan County. A short distance beyond is a cloverleaf interchange with I-81 near the Fordtown community, which serves Bristol (the third Tri-City) to the northeast and Knoxville to the southwest.
After interchanging with I-81, US 23 and I-26 curve sharply to the east, and sharply to the north immediately beyond. The freeway first has an interchange with SR 359 (Rock Springs Road), and one with an access road to the northern welcome center immediately beyond. Entering the outskirts of Kingsport, the freeway interchanges with SR 93 (Wilcox Drive, John B. Dennis Bypass), which serves as a bypass around the eastern side of Kingsport. The highway then ascends several hundred feet over the northern end of Bays Mountain, utilizing a northbound truck climbing lane and bypassing Kingsport to the west. It then descends this mountain, gaining a southbound truck climbing lane. Near the bottom of this descent, the highway crosses two railroads and then crosses the Holston River and the western end of Long Island, along with a third railroad, on a long pair of viaducts. Here, the freeway reaches its lowest elevation in Tennessee, at approximately . It then has a partial cloverleaf interchange with US 11W (West Stone Drive), where I-26 reaches its western terminus. The freeway meanders over the next few miles through a residential area, before reaching a partial interchange with the northern terminus of SR 36 (Lynn Garden Drive) and SR 346 (Carters Valley Road). A pair of one-lane ramps carry US 23 traffic through this interchange into Virginia at the north end, and the road continues into Virginia as a four-lane divided highway without access control.
History Background and predecessors The region that is now the northeastern corner of Tennessee was the first part of the state to be significantly explored and settled by European Americans. Longhunters from North Carolina and Virginia extensively explored the region in the 1750s and 1760s, which, at the time, was controlled by the Overhill Cherokee. These settlers utilized a series of Native American trails that traversed the region. By the late 1760s, the first permanent White settlements began to arise, which gradually developed into the cities along the present-day US 23 corridor of Elizabethton, Johnson City, Jonesborough, and Kingsport. These settlers founded the Watauga Association in 1772—a frontier pact generally regarded as the first constitutional government west of the Appalachian Mountains. The trail that would become part of US 19W through the Blue Ridge Mountains was utilized by the Overmountain Men—frontiersmen from west of the Blue Ridge Mountains who participated in the American Revolutionary War—in 1780. The East Tennessee and Western North Carolina Railroad, which came to be nicknamed the "Tweetsie", was chartered in 1866 for the purpose of transporting iron ore from mines in Cranberry, North Carolina. The first section, which ran between Hampton and Johnson City and passed through Elizabethton, opened in 1881. The tracks were completed into North Carolina the following year, providing the first efficient means of transportation across the mountains in this area. By 1890, a portion of the Clinchfield Railroad that ran through Kingsport, Johnson City, and Erwin was mostly complete. Also around this time, the network of trails that would become the US 23 corridor had also largely come into existence.
State and U.S. highway era
In 1915, the Tennessee Department of Highways and Public Works, the predecessor agency to TDOT, was established and tasked with establishing a state highway system. A proposal to construct a "wide road" between Johnson City and Asheville, North Carolina, reportedly existed as early as 1919. On October 1, 1923, the highway department established the Tennessee State Route System, the first numbered system of state highways in Tennessee. The network of roads that ran between the North Carolina state line at Spivey Gap and Kingsport were designated SR 36, and the short segment between Kingsport and the Virginia state line was designated SR 68. By 1928, SR 68 was renumbered as part of SR 36, and the former designation was applied to a different route. The portion of the route between the North Carolina state line at Spivey Gap and Johnson City became part of the Appalachian Scenic Highway auto trail in the mid-1920s. On November 11, 1926, the American Association of State Highway Officials (AASHO; predecessor agency to AASHTO) established the U.S. Numbered Highway System. An extension of US 23 was established by AASHO on May 26, 1930, with a complete concurrency with the road from the North Carolina state line at Spivey Gap to the Virginia state line in Kingsport. That same day, US 19W was established concurrent with the route from North Carolina to north of Johnson City. Signs were posted later that year. The road between Sam's Gap and US 19W/US 23 in Ernestville was designated as an extension of SR 81 in 1938. On June 8, 1951, AASHO approved a request by the North Carolina State Highway and Public Works Commission to reroute US 23 onto this road and the continuing North Carolina Highway 36 to the south.