U.S. Route 321
|Auxiliary route of US 21|
|Length||516.9 mi (831.9 km)|
|Western York Scenic Byway|
|South end||US 17 in Hardeeville, SC|
|North end||I-40 / SR 73 / SR 95 near Lenoir City, TN|
|States||South Carolina, North Carolina, Tennessee|
|Counties||SC: Jasper, Hampton, Allendale, Bamberg, Orangeburg, Lexington, Richland, Fairfield, Chester, York|
NC: Gaston, Lincoln, Catawba, Burke, Caldwell, Watauga, Avery
TN: Carter, Washington, Greene, Cocke, Sevier, Blount, Loudon
U.S. Route 321 (US 321) is a spur of U.S. Route 21. It runs for 516.9 miles (831.9 km) from Hardeeville, South Carolina to Lenoir City, Tennessee; with both serving as southern termini. It reaches its northernmost point at Elizabethton, Tennessee. Because of its unusual "north–south–north" routing, U.S. Route 321 intersects both Interstate 40 and U.S. Route 70 three separate times. The highway serves different roles in each state: An alternate route to interstates in South Carolina, a major highway in North Carolina, and a scenic route in Tennessee.
- 1 Route description
- 2 History
- 3 Future
- 4 Junction list
- 5 Special routes
- 6 References
- 7 External links
US 321 provides direct access between Savannah and Columbia, serving as an alternate to Interstate 95 and Interstate 26. Starting in Hardeeville, US 321 as a mostly 2 lane highway goes through sparsely populated areas and small towns including Estill, Fairfax, and Denmark, heading in a rather straight and northward direction into the Columbia area, widening to a 5 lane highway right after Neeses, then narrowing down to a 2 lane highway right after the town of North and widening to a 5 lane highway again after Swansea and staying that way until it merges with its parent route US 21 in Dixiana. In Columbia, the route stays concurrent with US 21 through Cayce, over the Congaree River on the Blossom Street Bridge, turning left onto Huger Street, right onto Elmwood Avenue, and left onto North Main Street. The roads separate at Hyatt Park, with US 321 staying west of I-77 and US 21 north of Columbia. The route goes through to communities of Winnsboro, Chester, York, and Clover before entering North Carolina at Bowling Green.
US 321 is an important route in Western North Carolina. It provides an alternative north–south route to I-77, which passes through a busy metropolitan area, and US 221, which is more twisty drive up the Appalachians. Travelers from South Carolina who are going to points west of Charlotte and want to avoid the traffic of I-77 may choose to enter the state on US 321.
The highway traverses through seven counties: Gaston, Lincoln, Catawba, Burke, Caldwell, Watauga, and Avery. US 321 has six control cities: Gastonia, Lincolnton, Hickory, Lenoir, Blowing Rock, and Boone.
US 321 is a multilane highway beginning at the state line. After 7 miles (11 km), it enters the Gastonia area. Traffic on northbound 321 through Gastonia is generally not as heavy as traffic on southbound 321 north of I-85, where it may back up for a couple of miles as drivers wait to turn onto I-85.
The road becomes a freeway at C. Grier Beam Boulevard in Gastonia, just south of NC 275/NC 279. It remains a freeway until just north of its junction with US 70 in Hickory. The freeway bypasses a number of cities that the old US 321 route once passed through. Today, US 321 Business follows the original 38-mile (61 km) route, which serves Maiden, Newton, and Conover, but the freeway is a more direct route to the mountains, and the business route is generally used by local traffic only.
Traffic is usually heavy between Hickory and Lenoir. The North Carolina Department of Transportation (NCDOT) has a long-term plan to widen the road to six lanes, which is expected to begin after 2020.
North of Lenoir, US 321 is a four-lane divided highway, continuing up the steep escarpment of the Blue Ridge Mountains. Until as recent as early 2018, the road was a narrow two-lane highway from near Patterson through Blowing Rock. Work on this area continued for much of the first two decades of the 21st century. The widening of US 321 through Blowing Rock was and continues to be seen as a controversial project. Many residents of the town felt that a four-lane highway would destroy the character of the small town, and they proposed several bypass alternatives. NCDOT selected the widening as its preferred alternative, but added several features such as underground utilities, sidewalks, landscaping, and rock walls to make the widening more palatable to the residents opposed to it. These features were not present on the two-lane highway that was replaced. The final portion of the widening project, at the steepest part of the road just south of Blowing Rock, began in 2012 and was completed in 2018. Some landscaping work remains which will commence in Fall 2018 as its own project, constructed separately for beautification of the route through town.
North of Blowing Rock, US 321 is already a highway of four lanes up to King Street in Boone; thus, US 321 is a four-lane highway from the South Carolina state line to downtown Boone. Currently,[when?] US 321 meets US 421 at King Street and overlaps it over King Street to leave town to the west. NCDOT project R-2615 is proposed to widen the US 321/421 concurrency from this junction to their junction near Vilas, although this project is currently unfunded. There is a feasibility study (FS-0511A) in progress[when?] to examine the possibility of widening US 321 from the junction near Vilas to the Tennessee state line. If both of these projects were completed, then US 321 would be a four-lane highway through the entire state.
As it crosses into Tennessee, US 321 enters the Cherokee National Forest, and continues westward through the rugged valley between Pond Mountain on the south and Watauga Lake on the north. The highway passes numerous campgrounds, boat launches, and other lake-related recreational areas as it winds its way along the shores of the lake. South of Butler, the highway joins SR 67, which enters from the Mountain City area to the northeast. The Appalachian Trail crosses US 321 at its intersection with Shook Gap Road, just before the highway exits the national forest. At Hampton, US 321 intersects US 19E, and the two highways run concurrently northward into Elizabethton.
US 321 "changes direction" in Elizabethton: the road is designated as southbound in both directions driving away from its intersection with US 19E. It is conterminous with US 11E through portions of Washington and Greene counties. In Greeneville, the highway continues south into Cocke County. At the Cocke-Greene County line US 321 becomes a four-laned divided highway and bypasses Parrottsville. The four-lane section ends just before US 321's junction with SR 160 and crossing I-40 at Newport.
The stretch of US 321 from Newport south to Cosby and southwest through Pittman Center to Gatlinburg parallels the northern boundary of the Great Smoky Mountains National Park and is quite scenic. From a point between Newport and Cosby to the intersection with the Little River Road, it is concurrent with SR 73. In Pigeon Forge, concurrent with US 441/Great Smoky Mountains Parkway, US 321 is a divided, multi-lane traffic-laden thoroughfare where it serves as the city's main route, lined with hotels, outlet malls and amusement facilities. Veering southwest of Pigeon Forge, the highway takes on a more rural character as it traverses Wears Valley, and narrows down to two lanes until its junction with SR 73 Scenic (the Little River Road) at the Townsend entrance to the park. It is concurrent with SR 73 from this junction to its terminus. With the exception of a 3-mile (4.8 km) section between Townsend and Maryville, the remaining portions of the highway through Blount County are a minimum of four lanes and usually a divided highway. Once the highway reaches Fort Loudon Dam in Loudon County, it crosses the Tennessee River via a bridge, completed in 2017, southeast of the dam then intersects with US 11 in Lenoir City. US 321 has a wrong-way concurrency with SR 95 from a point several miles south of Lenoir City (near Greenback) to its terminus at I-40. In the northern part of Lenoir City, US 321 intersects I-75 and US 70 before reaching I-40. Beyond I-40, the road continues northward to Oak Ridge as the two-lane SR 95.
US 321 is a four-lane semi-divided thoroughfare from I-40 and I-75 to the Great Smoky Mountains National Park, except for the 3-mile (4.8 km) stretch near Walland.
This section needs expansion. You can help by adding to it. (October 2017)
North Carolina Highway 17
|Location||Propst Crossroads–Boone, NC|
|Length||55.9 mi (90.0 km)|
North Carolina Highway 17 (NC 17) was an original state highway that traversed from Hickory to Boone, through Granite Falls, Hudson, Lenoir and Blowing Rock. In 1930, it was extended south on new primary routing to NC 113, in Propst Crossroads; also same year, US 321 was established in the state and overlapped NC 17 between Hickory and Boone. In 1934, NC 17 was decommissioned, with US 321 taking all north of Hickory and NC 96 taking all south.
North Carolina Highway 155
|Length||29.4 mi (47.3 km)|
North Carolina Highway 155 (NC 155) was established in 1994 following the old alignment of US 321 as it was moved onto new four-lane controlled-access highway. From NC 275/NC 279, in Dallas, it traversed north through High Shoals to Lincolnton. Sharing a short concurrency with NC 150 as it bypass the downtown area of Lincolnton, it continues north meeting with main US 321, south of Maiden, continuing in concurrency through Newton and finally Conover, where it ended at US 70. In 1999, the remainder of US 321 was moved onto new freeway bypass west of Newton and Conover; at same time, NC 155 was decommissioned and absorbed into US 321 Business.
North Carolina Highway 603
|Location||TN State Line–Sugar Grove, NC|
This section is empty. You can help by adding to it. (January 2019)
In addition to the widening project, there have also been talks of a freeway-to-freeway connection with Interstate 85 in Gastonia that would greatly relieve traffic flowing through the junction. Currently, US 321 is a surface road at the I-85 interchange, and is a limited access freeway a few hundred yards north. To extend the freeway to I-85, the remaining at-grade intersections and traffic lights would have to be eliminated. An interchange has been proposed to the Garden Parkway, which would terminate at the freeway section of US 321, bypassing the at-grade section, near Dallas.
|South Carolina||Jasper||Hardeeville||0.0||0.0||US 17 (Whyte Hardee Boulevard) – Ridgeland, Savannah|
|0.5||0.80||SC 46 east (Church Road)||To Millstone Landing|
|Tillman||12.5||20.1||SC 336 east (Tillman Road) – Ridgeland|
|Tarboro||19.8||31.9||US 601 north (Cypress Branch Road) – Hampton|
|Robertville||22.6||36.4||SC 462 (Gillson Branch Road) – Pineland|
|Hampton||Garnett||25.6||41.2||SC 119 south (Clyo Road) – Clyo, Springfield|
|Scotia||30.7||49.4||SC 333 (Scotia-Furman Highway) – Furman|
|Estill||35.8||57.6||SC 3 south (Third Street) – Lena||South end of SC 3 overlap|
|36.0||57.9||SC 3 north (Nixville Road) – Barnwell||North end of SC 3 overlap|
|||40.4||65.0||SC 363 east (Luray Highway) – Hampton||To Lake Warren State Park|
|Allendale||Fairfax||49.9||80.3||US 278 (Allendale-Hampton Highway) – Allendale, Hampton|
|Sycamore||55.6||89.5||SC 641 (Confederate Highway) – Allendale|
|Ulmer||59.9||96.4||US 301 south (Burton's Ferry Highway) – Allendale||South end of US 301 overlap|
|Bamberg||||61.9||99.6||US 301 north (Main Highway) – Bamberg||North end of US 301 overlap|
|Olar||66.5||107.0||SC 64 (Low Country Road) – Barnwell|
|Denmark||76.6||123.3||SC 70 south (Hagood Street) – Barnwell||South end of SC 70 overlap|
|||76.9||123.8||US 78 (Heritage Highway) – Bamberg, Blackville|
|||77.3||124.4||SC 70 north (Country Club Road) – Orangeburg||North end of SC 70 overlap|
|Orangeburg||Norway||85.3||137.3||SC 332 east (Cope Road) – Cope||East end of SC 332 overlap|
|85.6||137.8||SC 332 west / SC 400 east (Norway Road) – Springfield, Orangeburg||West end of SC 332 overlap|
|Neeses||90.9||146.3||SC 4 (Neeses Highway) – Springfield, Orangeburg|
|91.4||147.1||SC 389 west (Ninety Six Road) – Perry, Wagener|
|North||97.3||156.6||US 178 (North Highway) – Pelion, Orangeburg|
|Lexington||Swansea||105.1||169.1||SC 3 south (Whetstone Road) – Springfield, Blackville, Barnwell|
|105.9||170.4||SC 692 south (Fifth Street) – Orangeburg||To Swansea High Football Stadium|
|106.1||170.8||SC 6 west (Second Street) – Lexington||West end of SC 6 overlap|
|106.2||170.9||SC 6 east (First Street) – St. Matthews||East end of SC 6 overlap|
|||117.7||189.4||US 21 south / US 176 east (Charleston Highway) – Orangeburg||South end of US 21 and east end of US 176 overlap|
|Cayce||120.2||193.4||To I-77 north / Fish Hatchery Road – Charlotte|
|120.6||194.1||I-26 – Charleston, Spartanburg|
|121.8||196.0||SC 2 north (Frink Road)|
|West Columbia||123.3||198.4||SC 302 south (Airport Boulevard) – Aiken, Columbia Metropolitan Airport|
|125.0||201.2||SC 2 (State Street)|
|Richland||Columbia||126.5||203.6||US 1 / US 378 (Gervais Street)||To South Carolina State House|
|126.8||204.1||SC 12 (Hampton/Tylor Streets)||To Finlay Park and Columbia Museum of Art|
|127.4||205.0||I-126 west / US 76 west – Greenville, Spartanburg||West end of US 76 overlap|
|128.0||206.0||US 76 east (Elmwood Avenue)||East end of US 76 overlap|
|128.6||207.0||US 176 west (River Drive)||West end of US 176 overlap|
|129.2||207.9||SC 16 (Sunset Drive)|
|129.8||208.9||SC 215 north (Montichello Road)||To Columbia International University|
|130.8||210.5||US 21 north (Main Street)||North end of US 21 overlap; Columbia College at intersection|
|132.2||212.8||I-20 – Florence, Augusta|
|Fairfield||||151.2||243.3||SC 269 south (Hinnants Store Road)|
|Winnsboro Mills||152.4||245.3||SC 34 east – Ridgeway||East end of SC 34 overlap; to South Carolina Railroad Museum|
US 321 Bus. north (Columbia Road) / SC 213 west (Monjicono Road) – Monticello
|Winnsboro||156.1||251.2||SC 34 west (Newberry Road) / SC 200 east – Newberry, Great Falls||West end of SC 34 overlap|
US 321 Bus. south (Congress Street)
|Chester||Chester||178.8||287.8||SC 97 south (Great Falls Road) – Great Falls, Camden||South end of SC 97 overlap|
US 321 Bus. north (Columbia Road)
SC 9 south / SC 72 east / SC 97 north / SC 121 north (J.A. Cochran Bypass)
|South end of SC 9, east end of SC 72, and north end of SC 97/SC 121 overlap|
|181.2||291.6||SC 72 west / SC 121 south (West End Road) – Carlisle, Whitmire||West end of SC 72 and south end of SC 121 overlap|
SC 9 Bus. south (Pinckney Street)
|182.3||293.4||SC 9 north (Pinckney Street) – Lockhart||North end of SC 9 overlap|
US 321 Bus. south / SC 97 (Center Road) – Hickory Grove
|Lowrys||189.7||305.3||SC 909 south (Old York Road) – Lewis|
|York||McConnells||194.2||312.5||SC 322 west (Church Street)||West end of SC 322 overlap|
|194.3||312.7||SC 322 east (McConnells Highway) – Rock Hill||West end of SC 322 overlap; to Historic Brattonsville|
US 321 Bus. (Congress Street)
|203.7||327.8||SC 49 (Sharon Road) – Sharon, Union|
SC 5 Bus. / SC 161 Bus. south (Liberty Street) – Blacksburg
|South end of SC 161 Bus overlap|
US 321 Bus. (Kings Mountain Street)
|205.9||331.4||SC 5 / SC 161 south (Alexander Love Highway) – Blacksburg||South end of SC 161 and north end of SC 161 Bus overlap|
|Filbert||207.5||333.9||SC 161 north – Bethany||North end of SC 161 overlap|
|Clover||213.4||343.4||SC 55 (Kings Mountain/Bethel Streets) – Lake Wylie, Blacksburg|
|South Carolina–North Carolina state line|
|North Carolina||Gaston||Gastonia||7.3||11.7||Garrison Boulevard|
|7.9||12.7||US 29 / US 74 (Franklin Boulevard)|
|8.1||13.0||NC 7 east (Long Avenue)|
|9.4||15.1||I-85 – Charlotte, Spartanburg|
|Dallas||9.4||15.1||Grier Beem Boulevard – Gaston College||Signed exit 11|
US 321 Bus. north / NC 275 / NC 279 (Dallas-Cherryville Highway) – Cherryville
|Signed exits 12A-B Northbound and exit 12 Southbound|
|||16.1||25.9||Hardin Road||Signed exit 17|
US 321 Bus. (Gastonia Highway) – High Shoals, Lincolnton
|Signed exit 20|
|Lincolnton||23.6||38.0||NC 27 / NC 150 (Main Street) – Lincolnton||Signed exit 24|
US 321 Bus. (Maiden Highway) – Maiden
|Signed exit 28|
|Catawba||Maiden||32.3||52.0||Startown Road||Signed exit 33|
|||36.2||58.3||NC 10 – Newton||Signed exit 37|
|||40.1||64.5||River Road||Signed exit 41|
|Mountain View||41.4||66.6||NC 127 (Brookford Boulevard)||Signed exit 42|
|Hickory||42.3||68.1||I-40 – Statesville, Asheville||Signed exits 43A (east) and 43B (west)|
US 70 / US 321 Bus. south to NC 127 (Conover Boulevard) – Hickory
|Signed exit 44|
|45.3||72.9||Clement Boulevard – Hickory Regional Airport|
||No major junctions|
|Caldwell||Northlakes||47.9||77.1||US 321A north – Granite Falls|
|Granite Falls||50.1||80.6||Falls Avenue – Granite Falls|
|Lenoir||56.8||91.4||Southwest Boulevard – Morganton|
|59.1||95.1||US 321A south – Hudson|
|60.1||96.7||US 64 / NC 18 / NC 90 east – Lenoir, Wilkesboro||East end of NC 90 overlap|
|62.3||100.3||NC 90 west (Main Street) – Lenoir, Collettsville||West end of NC 90 overlap|
|||65.9||106.1||NC 268 east – Fort Defiance|
US 321 Bus. north (Main Street)
US 221 south / US 321 Bus. south
|South end of US 221 overlap|
|81.4||131.0||Blue Ridge Parkway||To Moses H. Cone Memorial Park and Julian Price Memorial Park|
|Boone||87.0||140.0||US 221 north / NC 105 – Linville, Banner Elk, Newland||North end of US 221 overlap|
|87.9||141.5||US 421 south / NC 194 north (King Street)||South end of US 421 and north end of NC 194 overlap|
|Vilas||93.6||150.6||NC 194 south – Valle Crucis||South end of NC 194 overlap|
|Sugar Grove||94.3||151.8||US 421 north – Mountain City||North end of US 421 overlap|
||No major junctions|
|North Carolina–Tennessee state line|
|Tennessee||Carter||||12.5||20.1||SR 67 east – Mountain City||East end of SR 67 and west end of SR 159 (hidden) overlap|
|Hampton||12.5||20.1||US 19E south (SR 37) – Roan Mountain||South end of US 19E overlap|
|Elizabethton||27.2||43.8||US 19E / SR 91 (SR 37) – Bluff City||North end of US 19E and SR 91 overlap|
|Route transition from northbound to southbound|
|28.0||45.1||SR 400 south – Watauga|
|31.3||50.4||SR 91 / SR 362 south||South end of SR 91 overlap|
|31.9||51.3||SR 359 south – Milligan College|
|Washington||Johnson City||35.3||56.8||Legion Street / Milligan Highway||Interchange|
|35.8||57.6||I-26 / US 19W / US 23 – Erwin, Kingsport||Intrechange; exit 24 (I-26)|
|36.7||59.1||SR 67 west / SR 381 (Cherokee Road)||West end of SR 67 and south end of SR 381 overlap|
|39.5||63.6||US 11E / SR 381 north (SR 34 / State of Franklin Road)||North end of US 11E and SR 381 overlap|
|Jonesborough||44.3||71.3||SR 354 (Boones Creek Road) / Boone Street – Boones Creek, Business District|
|To SR 81 / Washington Drive – Kingsport, Erwin, Business District|
|To SR 81 / Persimmon Ridge Road – Lamar, Erwin|
|Limestone||54.4||87.5||SR 75 north (Opie Arnold Road)|
|Greene||||58.0||93.3||SR 351 (Chuckey Pike) – Chuckey, Rheatown|
|Tusculum||62.6||100.7||SR 107 east (Tusculum Bypass) – Erwin, Tusculum College||East end of SR 107 (hidden) overlap|
|Greeneville||Erwin Highway – Tusculum, Tusculum College||Former SR 107|
US 11E Bus. south (SR 107 / Tusculum Boulevard)
|West end of SR 107 (hidden) overlap|
|66.0||106.2||Snapps Ferry Road||Interchange|
|67.1||108.0||US 11E south (SR 34) / SR 93 north (Kingsport Highway) – Kingsport, Morristown||South end of US 11E; southern terminus of SR 93|
|67.3||108.3||SR 172 north (Baileyton Road) – Baileyton, Airport||Southern terminus of SR 172|
US 11E Bus. north (SR 107 / Tusculum Boulevard)
|North end of US 11E Bus. overlap|
US 11E Bus. south (SR 350 / West Summer Street) / SR 350 north
|South end of US 11E Bus. overlap|
|68.5||110.2||SR 350 south (McKee Street)||South end of SR 350 (hidden) overlap|
|69.5||111.8||SR 70 / SR 107 west (Asheville Highway)||West end of SR 107 (hidden) overlap|
|71.3||114.7||SR 349 west (Warrensburg Road)|
|Cocke||Parrottsville||87.3||140.5||SR 340 – Parrottsville, Del Rio|
|||91.6||147.4||SR 160 north – Bybee|
|Newport||93.7||150.8||US 25 south / US 70 (SR 9 / Broadway Street)||South end of US 25 and east end of US 70 overlap|
|94.0||151.3||US 25 north (SR 9) / US 70 west (SR 35) / SR 32 north (Broadway Street)||North end of US 25 / SR 32 and west end of US 70 overlap|
|95.5||153.7||I-40 – Knoxville, Asheville|
|||101.1||162.7||SR 73 north (Wilton Springs Road)||North end of SR 73 (hidden) overlap|
|Cosby||106.0||170.6||SR 339 west (Jones Cove Road)|
|108.0||173.8||SR 32 south||South end of SR 32 overlap|
|Sevier||Pittman Center||119.9||193.0||SR 416 north|
|Gatlinburg–Pittman Center line||120.8||194.4||SR 454 north|
|Gatlinburg||126.1||202.9||US 441 south (SR 71) – Great Smoky Mountains National Park||South end of US 441 overlap|
|||127.2||204.7||Gatlinburg Parkway Bypass – Great Smoky Mountains National Park||No access from northbound US 441/US 321|
|Pigeon Forge||134.5||216.5||US 441 north (SR 71) / SR 71 – Sevierville||North end of US 441 overlap|
|Wears Valley||142.9||230.0||Foothills Parkway|
SR 73 Scenic east (East Lamar Alexander Parkway) – Great Smoky Mountains National Park
|Maryville||166.7||268.3||SR 447 north (Washington Street) to US 411 north|
|167.4||269.4||SR 336 south (Montvale Road)|
|167.6||269.7||US 411 / SR 33 (Broadway Avenue) – Rockford, Madisonville|
|168.7||271.5||US 129 / SR 115 – Alcoa, Knoxville|
|171.0||275.2||SR 335 north (Old Glory Road)||North end of SR 335 overlap|
|171.6||276.2||SR 335 south (William Blount Drive)||South end of SR 335 overlap|
|Friendsville||176.1||283.4||SR 333 north (Main Avenue)|
|Loudon||||181.4||291.9||SR 95 south (Lenoir City Road) – Greenback||South end of SR 95 (hidden) overlap|
|||185.0||297.7||SR 444 west (Tellico Parkway) – Tellico Village|
|Lenoir City||186.8||300.6||US 11 / SR 2 (Broadway Street) – Knoxville, Loudon, Farragut|
|189.5||305.0||I-75 – Knoxville, Chattanooga|
|190.3||306.3||US 70 / SR 1 (Kingston Pike) – Knoxville, Kingston|
|194.2||312.5||I-40 / SR 95 north – Knoxville, Nashville||West end of SR 73 (hidden) and north end of SR 95 (hidden) overlap|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
Winnsboro business loop
|Location||Winnsboro, South Carolina|
|Length||4.2 mi (6.8 km)|
U.S. Route 321 Business (US 321 Bus) was established around 1951 or 1952, when mainline US 321 was rerouted west, bypassing Winnsboro. US 321 Bus traverses through Winnsboro Mills, via Columbia Road, and downtown Winnsboro, via Congress Street.
Chester business loop
|Location||Chester, South Carolina|
|Length||3.7 mi (6.0 km)|
U.S. Route 321 Business (US 321 Bus) was established between 1962-1964, when mainline US 321 was rerouted west, bypassing Chester. US 321 Bus traverses through downtown Chester, via Columbia Street and Center Road.
York business loop
|Location||York, South Carolina|
|Length||2.5 mi (4.0 km)|
U.S. Route 321 Business (US 321 Bus) was established around 1957-1958, when mainline US 321 was rerouted west, bypassing York. US 321 Bus traverses through downtown York, via Congress Street and Kings Mountain Street.
Dallas–Hickory business loop
|Length||37.2 mi (59.9 km)|
U.S. Route 321 Business (US 321 Bus) was established in June, 1999, as a renumbering all of NC 155 and part of mainline US 321 in Catawba County. Traversing 37.2 miles (59.9 km) through Gaston, Lincoln and Catawba counties, it connects the cities and towns of Dallas, High Shoals, Lincolnton, Maiden, Newton, Conover and Hickory. The highway follows the original US 321 routing through that existed prior to 1994.
Lincolnton alternate route
|Location||Lincolnton, North Carolina|
|Length||3.4 mi (5.5 km)|
U.S. Route 321 Alternate (US 321A) was established 1956 when mainline US 321 was placed on new bypass east of downtown Lincolnton. It traversed along Aspen Street and around the Lincoln County Civil Court on Court Square Drive. In 1960 it was decommissioned, with Aspen Street becoming secondary roads.
Granite Falls–Lenoir alternate route
|Location||Granite Falls–Lenoir, NC|
|Length||11.8 mi (19.0 km)|
U.S. Route 321 Alternate (US 321A) was established 1948 as a number swap with US 321 through downtown Lenoir. In 1957, US 321A was extended south, replacing mainline US 321 through Hudson and Granite Falls, ending at its current southern terminus north of the Catawba River. In June, 1964, US 321A was placed on one-way splits through downtown Lenoir; northbound continued along Mulberry Street and West Avenue, southbound rerouted along Main Street and College Avenue. In September, 2006, US 321A was rerouted to its current northern terminus, just south of downtown Lenoir, via McLean Drive. Its old alignment through downtown Lenoir was carried on by NC 90 until 2012, when it too was rerouted; the old alignment is now under city control.
Traversing through Granite Falls, Sawmills, Hudson and Lenoir US 321A has not changed much over the years. Predominantly a two-lane highway, it parallels a short line railroad and connects to several factories.
Lenoir alternate route
|Location||Lenoir, North Carolina|
|Length||5.9 mi (9.5 km)|
U.S. Route 321 Alternate (US 321A) was established 1941 as a new alternate route bypassing Lenoir. In 1948, it was replaced by mainline US 321.
Blowing Rock business loop
|Location||Blowing Rock, North Carolina|
|Length||2.0 mi (3.2 km)|
U.S. Route 321 Business (US 321 Bus) was established 1960 as an upgrade to secondary roads through downtown Blowing Rock; which were originally part of mainline US 321 until about 1954, when it was moved onto a new bypass east. The highway traverses along Main Street and shares a concurrency with US 221 for 0.8 miles (1.3 km) on its northern section.
Boone truck route
|Location||Boone, North Carolina|
|Length||4.0 mi (6.4 km)|
U.S. Route 321 Truck (US 321 Truck) redirects truckers traveling through the area to go south and around downtown Boone, via NC 105 and NC Highway 105 Bypass (SR-1107). The shares some overlap with US 221 Truck and complete overlap with US 421 Truck.
Greeneville truck route
|Length||3.6 mi (5.8 km)|
U.S. Route 321 Truck (US 321 Truck) redirects truckers traveling south on US 321 around downtown. It shares a concurrency with US 11E and SR 70. The route begins at US 11E/US 321 and ends 3.6 miles (5.8 km) later at US 321/SR 70.
|0.0||0.0||US 321 / SR 35 (West Main Street) / SR 70 south (Asheville Highway) / SR 107 (Asheville Highway / West Main Street) – Greeneville, Parrottsville, Newport, Del Rio, Asheville||Southern terminus of US 321 Truck and end SR 70 overlap|
US 11E Bus. north (West Summer Street) / SR 350 south (West Summer Street) – Downtown Greeneville
|Begin US 11E Business concurrency; Northern terminus of SR 350|
|1.2||1.9||US 11E south / SR 34 south (West Andrew Johnson Highway) / Blue Springs Parkway – Mosheim, Bulls Gap, Morristown||Southern terminus of US 11E Business; Begin US 11E/SR 34 overlap|
|1.7||2.7||SR 70 north (Lonesome Pine Trail) – Romeo, Rogersville||End SR 70 overlap|
|2.0||3.2||SR 172 north (Baileyton Road) / WhiteHouse Road – Baileyton, Airport||Southern terminus of SR 172; Interchange|
|3.4||5.5||US 11E north / US 321 (North Main Street / East Andrew Johnson Highway) / SR 34 north (East Andrew Johnson Highway) / SR 35 south (North Main Street) – Jonesborough, Johnson City, Newport, Downtown Greeneville||End US 321 Truck|
|3.6||5.8||SR 93 north (Kingsport Highway) – Fall Branch, Kingsport||Southern terminus of SR 93|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- Google (December 22, 2013). "U.S. Route 321 in South Carolina" (Map). Google Maps. Google. Retrieved December 22, 2013.
- Google (December 22, 2013). "U.S. Route 321 in North Carolina" (Map). Google Maps. Google. Retrieved December 22, 2013.
- Google (December 22, 2013). "U.S. Route 321 in Tennessee" (Map). Google Maps. Google. Retrieved December 22, 2013.
- webmaster. "NCDOT: U.S. 321 Widening from Hickory to Lenoir". www.NCDOT.gov. Retrieved January 17, 2018.
- "NCDOT: US 321 Improvements, Blowing Rock". Retrieved October 22, 2010.
- "U.S. 321 Widening Project in Blowing Rock Continues, Hopefully Finished by Winter - High Country Press". www.HCPress.com. Retrieved January 17, 2018.
- "NCDOT: TIP".
- "The US 321 Directional Change". Retrieved 2010-10-22.
- Google (May 18, 2014). "North Carolina Highway 17" (Map). Google Maps. Google. Retrieved May 18, 2014.
- State Highway System of North Carolina (PDF) (Map). Cartography by NCDOT. North Carolina Department of Transportation. 1930. Retrieved May 18, 2014.
- North Carolina Primary Highway System (PDF) (Map). Cartography by NCDOT. North Carolina Department of Transportation. 1940. Retrieved May 18, 2014.
- Google (May 18, 2014). "North Carolina Highway 155" (Map). Google Maps. Google. Retrieved May 18, 2014.
- "Route Change (1994-10-18)" (PDF). North Carolina Department of Transportation. October 18, 1994. Retrieved May 18, 2014.
- "Route Change (1999-06-25)" (PDF). North Carolina Department of Transportation. June 25, 1999. Retrieved May 18, 2014.
- Google (December 1, 2013). "US 321 Business - Winnsboro, South Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321 Business - Chester, South Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321 Business - York, South Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321 Business - Dallas-Hickory, North Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321A - Lincolnton, North Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321A - Granite Falls-Lenoir, North Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- "US 321A Route Change (1964-06-04)" (PDF). North Carolina Department of Transportation. June 4, 1964. Retrieved December 1, 2013.
- "US 321A Route Change (2006-09-07)" (PDF). North Carolina Department of Transportation. September 7, 2006. Retrieved December 1, 2013.
- "Correction to Caldwell County Route" (PDF). North Carolina Department of Transportation. December 11, 2012. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321A - Lenoir, North Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 1, 2013). "US 321 Business - Blowing Rock, North Carolina" (Map). Google Maps. Google. Retrieved December 1, 2013.
- Google (December 4, 2013). "US 321 Truck - Boone, North Carolina" (Map). Google Maps. Google. Retrieved December 4, 2013.
- "U.S. 321 widening to take longer than estimated" by Andrew Mackie, Hickory Daily Record, March 14, 2006