U.S. Route 321

U.S. Route 321
US 321 highlighted in red
Route information
Auxiliary route of US 21
Length	516.9 mi[1][2][3] (831.9 km)
Existed	1931–present
Tourist routes	Western York Scenic Byway
Major junctions
South end	US 17 in Hardeeville, SC
Major intersections	I-26 in Cayce, SC I-20 in Columbia, SC I-85 in Gastonia, NC I-40 in Hickory, NC I-26 / US 19W / US 23 in Johnson City, TN I-40 in Newport, TN I-75 in Lenoir City, TN
North end	I-40 / SR 73 / SR 95 near Lenoir City, TN
Location
Country	United States
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: Johnson, Carter, Washington, Greene, Cocke, Sevier, Blount, Loudon
Highway system
United States Numbered Highway System List Special Divided
← SC 319 SC → SC 322 ← US 311 NC → NC 343 ← SR 320 TN → SR 321

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, just northeast of Johnson City. 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.

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.^[4]

North of Lenoir, US 321 is a four-lane divided highway, continuing up the steep escarpment of the Blue Ridge Mountains. Until 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.^[5] 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.^[6] 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.^[7] 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 inverts directions in Elizabethton: the road is designated as southbound in both directions driving away from its intersection with US 19E.^[8] 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[9] (90.0 km)
Existed	1921–1934

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.^[10] In 1934, NC 17 was decommissioned, with US 321 taking all north of Hickory and NC 96 taking all south.^[11]

North Carolina Highway 155
Location	Dallas–Conover, NC
Length	29.4 mi[12] (47.3 km)
Existed	1994–1999

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.^[13] 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.^[14]

North Carolina Highway 603
Location	TN State Line–Sugar Grove, NC
Existed	1931–1961

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^{[citation needed]}. 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.

State	County	Location	mi [1][2][3]	km	Destinations	Notes
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	Southern terminus of US  601
		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			SC 48 Truck east (Blossom Street east / US 21 Conn. east / US 76 Conn. east)	Western terminus of US 21 Conn., the western segment of US 76 Conn., SC 48 Truck, and Blossom Street; US 21, US 176, and US 321 turn left off of Blossom Street onto Huger Street.
			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
			152.7	245.7	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
			156.9	252.5	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
			179.4	288.7	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
			182.0	292.9	SC 9 Bus. south (Pinckney Street)
			182.3	293.4	SC 9 north (Pinckney Street) – Lockhart	North end of SC 9 overlap
			184.2	296.4	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
		York	203.3	327.2	US 321 Bus. (Congress Street)
			203.7	327.8	SC 49 (Sharon Road) – Sharon, Union
			204.5	329.1	SC 5 Bus. / SC 161 Bus. south (Liberty Street) – Blacksburg	South end of SC 161 Bus overlap
			205.7	331.0	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
			217.2 0.0	349.5 0.0	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
			11.7	18.8	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
	Lincoln	​	18.8	30.3	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
		​	27.0	43.5	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)
			43.3	69.7	US 70 / US 321 Bus. south to NC 127 (Conover Boulevard) – Hickory	Signed exit 44
			45.3	72.9	Clement Boulevard – Hickory Regional Airport
	Burke	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
	Watauga	Blowing Rock	79.4	127.8	US 321 Bus. north (Main Street)
			80.6	129.7	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
	Avery	No major junctions
			105.5 0.0	169.8 0.0	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
			65.2	104.9	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 overlap; southern terminus of SR 93
			67.3	108.3	SR 172 north (Baileyton Road) – Baileyton, Airport	Southern terminus of SR 172
			68.0	109.4	US 11E Bus. north (SR 107 / Tusculum Boulevard)	North end of US 11E Bus. overlap
			68.4	110.1	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)	Eastern terminus of SR 349
	Cocke	Parrottsville	87.3	140.5	SR 340 – Parrottsville, Del Rio
		​	91.6	147.4	SR 160 north – Bybee	Southern terminus of SR 160
		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	I-40 exit 435
		​	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) – Cherokee Hills	Eastern terminus of SR 339
			106.2	170.9	Foothills Parkway to I-40	Western terminus of section 8A of the Foothills Parkway
			108.0	173.8	SR 32 south	South end of SR 32 overlap
	Sevier	Pittman Center	119.9	193.0	SR 416 north (Pittman Center Road)	Southern terminus of SR 416
		Gatlinburg–Pittman Center line	120.8	194.4	SR 454 north (Buckhorn Road)	Southern terminus of SR 454
		Gatlinburg	126.1	202.9	US 441 south / SR 73 Scenic west (Parkway/SR 71) – Great Smoky Mountains National Park	South end of US 441 overlap; eastern terminus of SR 73 Scenic
			127.2	204.7	Gatlinburg Parkway Bypass – Great Smoky Mountains National Park	No access from northbound US 441/US 321
		Pigeon Forge			SR 449 north (Dollywood Lane) – Dollywood	Southern terminus of SR 449
			134.5	216.5	US 441 north (Parkway/SR 71) – Sevierville	North end of US 441 overlap
		Wears Valley	142.9	230.0	Foothills Parkway	Interchange; eastern terminus of western section of Foothills Parkway
	Blount	Townsend	149.4	240.4	SR 73 Scenic east (East Lamar Alexander Parkway/SR 337) – Great Smoky Mountains National Park	Western terminus of SR 73 Scenic
		Walland	156.8	252.3	Foothills Parkway – Top of The World, Chilhowee Lake, Great Smoky Mountains National Park Look Rock area	Interchange
		Maryville	166.7	268.3	SR 447 north (Washington Street) to US 411 north	Southern terminus of SR 447
			167.4	269.4	SR 336 south (Montvale Road)	Northern terminus of SR 336
			167.6	269.7	US 411 (Broadway Avenue/SR 33) – 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) – Friendsville	Southern terminus of SR 333
	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	Eastern terminus of SR 444
		Lenoir City	186.8	300.6	US 11 (Broadway Street/SR 2) – Knoxville, Loudon, Farragut
			189.5	305.0	I-75 – Knoxville, Chattanooga	I-75 exit 81
			190.3	306.3	US 70 (Kingston Pike/SR 1) – Knoxville, Kingston
			194.2	312.5	I-40 / SR 95 north (White Wing Road) – Knoxville, Nashville, Oak Ridge	West end of SR 73 (hidden) and north end of SR 95 (hidden) overlap; I-40 exit 364
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Route transition       Unopened

U.S. Highway 321 Business
Location	Winnsboro, South Carolina
Length	4.350 mi[15] (7.001 km)
Existed	1952[citation needed]–present

U.S. Route 321 Business (US 321 Bus.) is a 4.350-mile (7.001 km) business route of US 321 that exists in Winnsboro Mills and Winnsboro, via Columbia Road and Congress Street.^[16] It was established around 1951 or 1952, when mainline US 321 was rerouted west, bypassing Winnsboro.^{[citation needed]}

U.S. Highway 321 Business
Location	Chester, South Carolina
Length	3.670 mi[17] (5.906 km)
Existed	1964[citation needed]–present

U.S. Route 321 Business (US 321 Bus.) is a 3.670-mile (5.906 km) business route of US 321 in the city of Chester. It traverses downtown Chester, via Columbia Street and Center Road.^[18] It was established between 1962 and 1964, when mainline US 321 was rerouted west, bypassing Chester.^{[citation needed]}

U.S. Highway 321 Business
Location	York, South Carolina
Length	2.500 mi[19] (4.023 km)
Existed	1958[citation needed]–present

U.S. Route 321 Business (US 321 Bus.) is a 2.500-mile (4.023 km) business route of US 321 in the city of York, utilizing Congress Street and Kings Mountain Street.^[20] It was established around 1957–1958, when mainline US 321 was rerouted west, bypassing York.^{[citation needed]}

U.S. Highway 321 Business
Location	Dallas–Hickory, NC
Length	37.2 mi[21] (59.9 km)
Existed	1999–present

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.^[14]

U.S. Highway 321A
Location	Lincolnton, North Carolina
Length	3.4 mi[22] (5.5 km)
Existed	1956–1960

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.

U.S. Highway 321A
Location	Granite Falls–Lenoir, NC
Length	11.8 mi[23] (19.0 km)
Existed	1948–present

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 Granite Falls and Hudson, 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.^[24][25][26]

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 and downtowns.

U.S. Highway 321A
Location	Lenoir, North Carolina
Length	5.9 mi[27] (9.5 km)
Existed	1941–1948

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.

U.S. Highway 321 Business
Location	Blowing Rock, North Carolina
Length	2.0 mi[28] (3.2 km)
Existed	1960–present

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.

U.S. Highway 321 Truck
Location	Boone, North Carolina
Length	4.0 mi[29] (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.

U.S. Route 321 Truck
Location	Greeneville, Tennessee
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.

The entire route is in Greeneville, Greene County.

mi	km	Destinations	Notes
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
1.0	1.6	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       Concurrency terminus

• U.S. roads portal

• "U.S. 321 widening to take longer than estimated" by Andrew Mackie, Hickory Daily Record, March 14, 2006

• Media related to U.S. Route 321 at Wikimedia Commons
• Mapmikey's South Carolina Highways Page: U.S. Route 321
• NCRoads.com: U.S. Route 321
• NCRoads.com: U.S. Route 321-A
• NCRoads.com: U.S. Route 321 Business
• Endpoints of U.S. Highway 321