Several special routes of U.S. Route 15 (US 15) exist. In order from south to north, they are as follows.

South Carolina

Walterboro–Creedmoor alternate route

U.S. Highway 15 Alternate (US 15 Alt.) in South Carolina and U.S. Highway 15A (US 15A) in North Carolina was established in 1936 as a renumbering of US 401, from Walterboro, South Carolina, to Creedmoor, North Carolina, going through the cities of Laurinburg, Raeford, Fayetteville, Lillington, and Raleigh. In 1950, South Carolina discontinued the US 15A concurrency with US 15, but it was not until 1953 when North Carolina followed and moved US 15A's southern terminus in Laurinburg. In 1957, US 15A was renumbered back to US 401.

Santee connector route

U.S. Highway 15 Connector (US 15 Conn.) is a connector route that connects US 15/US 301 at the SCHP Patrolman Harry B. Ray Memorial Intersection just southwest of Santee, South Carolina, with South Carolina Highway 6 (SC 6) in the northeastern part of the town.

Summerton connector route

U.S. Highway 15 Connector (US 15 Conn.) is a connector route that connects US 301 with US 15 within the city limits of Summerton, South Carolina. It is known as Railroad Avenue and is an unsigned highway.

Sumter connector route

U.S. Highway 15 Connector (US 15 Conn.) is a connector route that connects US 15 with US 521 within the city limits of Sumter, South Carolina. Each of its terminuses is on the Sumter–South Sumter line. It is unnamed and is an unsigned highway.

Sumter–Society Hill alternate route

U.S. Highway 15 Alternate (US 15 Alt.) was an alternate route of US 15 that ran from Sumter to Society Hill, South Carolina. In 1957, it was decommissioned and replaced by US 401.

Dubose–Manville alternate route

Hartsville alternate route

Hartsville business loop

U.S. Highway 15 Business (US 15 Bus.) is a business route of US 15 in Hartsville, South Carolina. It starts at US 15 outside of Hartsville. It then intersects SC 151 Bus. in the center of Hartsville and SC 102 in North Hartsville. It then ends at US 15.

Major intersections

Hartsville truck route

Bennettsville business loop

U.S. Highway 15 Business (US 15 Bus.) was a business loop of US 15 that ran through Bennettsville, South Carolina. In 1990, it was decommissioned and replaced by SC 385.

North Carolina

Laurinburg business loop

U.S. Highway 15 Business (US 15 Bus.) was established between 1960 and 1962 following the original mainline US 15 route through Laurinburg, North Carolina. US 15 Bus., in concurrency partly with US 401 Bus. and US 501 Bus., traversed along Main Street and Aberdeen Road.

Major intersections

Sanford alternate route

U.S. Highway 15A (US 15A) was established in 1957 when mainline US 15 was bypassed west of Sanford, North Carolina. US 15A, in concurrency with US 1A and US 501A, traversed on Carthage Street and Hawkins Avenue. In 1960, it was renumbered as US 15 Bus.

Sanford business loop

U.S. Highway 15 Business (US 15 Bus.) in Sanford, North Carolina, was established in 1960 as a renumbering of US 15A along Carthage Street and Hawkins Avenue, in concurrency with US 1 Bus. and US 501 Bus. Between 1976 and 1978, US 1 Bus. was rerouted along North Carolina Highway 42 on Wicker Street; it is believed that both US 15 Bus. and US 501 Bus. were decommissioned by that time.

Sanford bypass route

Chapel Hill alternate route

U.S. Highway 15A (US 15A) was established in 1953 when mainline US 15 was bypassed around Chapel Hill, North Carolina. US 15A, in concurrency with US 501A, traversed on Columbia and Franklin streets. In 1960, it was renumbered as US 15 Bus.

Chapel Hill business loop

U.S. Highway 15 Business (US 15 Bus.) in Chapel Hill, North Carolina, was established in 1960 as a renumbering of US 15A along Columbia and Franklin streets, in concurrency with US 501 Bus. It was decommissioned between 1985 and 1987.

Durham business loop

U.S. Highway 15 Business (US 15 Bus.) was established in 1960 as a renumbering of mainline US 15, along University Drive and Roxboro Street, through downtown Durham, North Carolina. It is in concurrency with US 501 Bus. for majority of its route and is relatively unchanged since inception.

Major intersections

Durham bypass route

Oxford truck route

Virginia

Clarksville business route

Keysville business loop

U.S. Route 15 Business (US 15 Bus.) is a business route of US 15 in Charlotte County, Virginia. The highway, which runs between junctions with US 360 and US 15 south and north of Keysville, is entirely concurrent with US 360 Bus. US 15 Bus./US 360 Bus. follow Old Kings Highway from its southern end through a partial interchange with US 15 and US 360 to the town of Keysville. The business routes enter the town on King Street, along which the highways are concurrent with State Route 40 (SR 40). In the center of Keysville, US 15 Bus., US 360 Bus., and SR 40 curve north then west to cross the Southern Virginia Railroad. Just west of the railroad, the business routes turn north onto Front Street. US 15 Bus./US 360 Bus. follows Four Locust Highway to rejoin their respective mainline highways at a partial cloverleaf interchange.Charlotte County (PDF)

Farmville business loop

U.S. Route 15 Business (US 15 Bus.) in Farmville, Virginia, is a former segment of US 15 that begins at the southern end of an overlap at a diamond interchange with US 460. The route follows South Main Street directly into Farmville until the intersection with US 460 Bus. and SR 45 and turns west in its own concurrency with US 460 Bus. The US 15/US 460 concurrency ends when US 15 Bus. terminates just north of a trumpet interchange at the north end of the mainline US 15/US 460 overlap, but US 460 turns south an ends directly at that trumpet interchange with US 460.

Farmville alternate loop

U.S. Route 15 Alternate (US 15 Alt.) in Farmville, Virginia, is an alternate route of US 15 Bus. The route diverges from US 15 Bus. at Griffin Boulevard south of downtown Farmville. It follows Griffin Boulevard north to High Street, then turns northwest along Oak Street. It rejoins US 15 Bus. and US 460 Bus. just west of downtown Farmville.

Culpeper business loop

U.S. Route 15 Business (US 15 Bus.) in Culpeper, Virginia, is a former segment of US 15 that begins at the southern end of an overlap at a diamond interchange, that being with US 29, where the mainline road turns east. The first leg of US 15 Bus. is Orange Road, and, despite the fact that Orange Road continues past US 522 to terminate as US 29 Bus., US 15 Bus. joins US 522 northwest in an overlap that meets US 29 Bus., where Madison Road becomes South Main Street. Along US 15 Bus./US 29 Bus./US 522, Orange Road terminates between West Park Avenue and West and East Mason streets. The intersection of Culpeper Street is where one can find Culpeper station if they turn east and drive two blocks away. US 522 turns left on West Evans Street, while, four blocks later, US 15 Bus./US 29 Bus. turns east off of North Main Street onto Old James Madison Highway, which eventually becomes Brandy Road and runs parallel to the same Amtrak line that used Culpeper station before terminating at an interchange with the US 15/US 29 overlap. Brandy Road becomes SR 762.

Remington business loop

U.S. Route 15 Business (US 15 Bus.), completely concurrent with US 29 Bus., is the former two-lane route of US 15/US 29 (James Madison Highway) through the town of Remington, Virginia, bypassed in 1975. It begins in Culpeper County where the bypass curves to the north, while US 15 Bus./US 29 Bus. heads northeast on Remington Road to a 1930 pony truss bridge over the Rappahannock River.Bridgehunter.com: Remington Road Bridge (National Bridge Inventory data) Crossing the bridge into Fauquier County, it soon enters Remington, where it is known as James Madison Street. The principal intersection in Remington is with Main Street (SR 651), which heads west to the bypass and east to Sumerduck. After leaving Remington, US 15 Bus./US 29 Bus. travels north and returns to mainline US 15/US 29 about south of SR 28.

River Road (SR 1202), which intersects US 15 Bus./US 29 Bus. north of the Rappahannock River, is the pre-1930 alignment of US 15 (then also SR 32).Remington quadrangle (advance sheet), 1927 The original bridge is long-gone.

Warrenton business loop

U.S. Route 15 Business (US 15 Bus.) in Warrenton, Virginia, is also US 17 Bus. and US 29 Bus., at least at the southern end. After James Madison Highway becomes Shirley Avenue, US 15 Bus. leaves this concurrency at Falmouth Street, while US 17 Bus./US 29 Bus. continues to the northwest. Two blocks after serving as the western terminus of SR 643, Falmouth Street intersects Mockingbird Lane and curves west to become Main Street, which runs through the heart of historic downtown Warrenton. As Main Street terminates at the corner of US 211 Bus. (Waterloo Street and Alexandria Pike), US 15 Bus. turns north in a concurrency with US 211 Bus. US 15 Bus./US 211 Bus. follows Alexandria Pike north until they move onto Blackwell Road before encountering at US 211/US 29 Bus. (Lee Highway) where US 211 and US 211 Bus. terminates, Blackwell Road becomes SR 672, and US 15 Bus. turns east on US 29 Bus. before finally terminating at an interchange with the northern end of the US 15/US 17/US 29 overlap.

Warrenton–Aldie temporary route

Leesburg business loop

U.S. Route 15 Business (US 15 Bus.) separates from US 15 at SR 7 as it enters the town of Leesburg, Virginia, from the south as South King Street, following the Leesburg Bypass. It continues straight into the historic downtown area, crossing the Washington and Old Dominion Railroad Trail, the Town Branch creek, Royal Street, and Loudoun Street. US 15 Bus. crosses Market Street, SR 7 Bus., at the center of town, from which the town's four intercardinal sections radiate, and where the Loudoun County courthouse occupies the northeast corner. US 15 Bus. then changes names to North King Street and proceeds through the last few blocks of the historic district, crossing Cornwall and North streets. It continues past Union Cemetery, Ida Lee Park, and several schools. US 15 Bus. rejoins US 15 at the north end of Leesburg, just short of the Morven Park equestrian facilities.

Leesburg bypass route

Maryland

Emmitsburg business loop

U.S. Route 15 Business (US 15 Bus.) is a business route of US 15 through Emmitsburg, Maryland. Known as Seton Avenue, the highway runs between junctions with US 15 on the south and north sides of the town. US 15 Bus. follows the original alignment of US 15 through Emmitsburg. The highway serves the Saint Joseph College and Mother Seton Shrine campusses, which are home to several emergency management institutions and a shrine dedicated to Elizabeth Ann Seton, the first person born in the U.S. to be canonized by the Catholic Church. The U.S. Highway's bypass of the town was constructed between 1963 and 1965. US 15 Bus. was assigned to the old alignment of US 15 from south of Emmitsburg to the Pennsylvania state line by 1967. The business route became unsigned by 1989 and was truncated at its present northern end by 1999.