# Special routes of U.S. Route 521

Four special routes of U.S. Route 521 exist, and two others have existed in the past. In order from south to north they are as follows.

## Existing routes
### Andrews business loop

U.S. Route 521 Business (US 521 Bus.) is a 3.420 miles (5.504 km) business route of US 521 that travels through downtown Andrews, via Main Street. It follows the old US 521 mainline route.
The entire route is in Georgetown County.
| Location | mi | km | Destinations | Notes |
| ​ | 0.000 | 0.000 | US 521 (Georgetown Highway) – Manning | Southern terminus; flyover interchange |
| Andrews | 2.410 | 3.879 | SC 41 Bus. (Morgan Avenue) – Jamestown, Hemingway | |
| Andrews | 3.420 | 5.504 | US 521 south / SC 41 south (County Line Road) – Charleston, Georgetown US 521 north – Kingstree, Manning SC 41 north (County Line Road) – Hemingway, Andrews High School | Northern terminus |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi |||||

### Camden truck route 1

U.S. Route 521 Truck (US 521 Truck) is a truck route of US 521 to direct truck traffic to avoid downtown Camden. The highway takes various roads including: Ehrenclou Drive, Chestnut Ferry Road, Jefferson Davis Highway (in concurrency with US 1/US 601/SC 34), Springdale Drive, and Boykin Road (in concurrency with US 601 Truck). Nearly the entire length of the truck route is within the city limits of Camden.
The entire route is in Camden, Kershaw County.
| mi | km | Destinations | Notes |
| 0.0 | 0.0 | US 1 Truck north / US 521 (South Broad Street) to I-20 | Southern terminus of US 1 Truck and US 521 Truck |
| | | US 1 north / US 601 north (West DeKalb Street / SC 34 east) | Southern end of US 1/US 601/SC 34 concurrency |
| | | Senator Donald H. Don Holland Memorial Bridge | Crossing over railroad tracks of CSX |
| | | US 1 south / US 601 south (West DeKalb Street / SC 34) / US 601 Truck begins | Northern end of US 1/US 601/SC 34 concurrency; southern end of US 601 Truck concurrency; southern terminus of US 601 Truck |
| | | SC 97 (Liberty Hill Road) | |
| | | US 521 / US 601 (Kershaw Road) | Northern end of US 601 Truck concurrency; northern terminus of US 521 Truck and US 601 Truck |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus ||||

### Camden truck route 2

U.S. Route 521 Truck (US 521 Truck) is a 0.830-mile (1.336 km) truck route of US 521 that exists entirely within the southern part of Camden. It uses York Street and Mill Street to connect US 521 (Broad Street) with US 1/SC 34 (East Dekalb Street). It is entirely concurrent with SC 34 Truck. The southbound lanes are also part of US 1 Truck, with no indication of US 1 Truck or SC 34 Truck; the northbound lanes have no indication of US 521 Truck.

### Kershaw business loop

U.S. Route 521 Business (US 521 Bus.) is a 1.500-mile (2.414 km) business route of US 521 that exists in Kershaw. It travels through downtown, via Hampton Street. It also has a concurrency with US 601 Bus. It follows the former path of US 521.
The entire route is in Lancaster County.
| Location | mi | km | Destinations | Notes |
| Kershaw | 0.000 | 0.000 | US 521 / US 601 (Hampton Street) – Carolina Motorsports Park | Southern end of US 601 Bus. concurrency; southern terminus of US 521 Bus. and US 601 Bus. |
| Kershaw | 0.480 | 0.772 | SC 341 south (Marion Street) – Bethune | Northern terminus of SC 341 |
| Kershaw | 0.760 | 1.223 | Hilton Street (US 521 Truck south / US 601 / SC 157 Truck / SC 341 Truck) – Jefferson, Pageland | Northern end of US 601 Bus. concurrency; northern terminus of US 521 Truck and US 601 Bus. |
| ​ | 1.500 | 2.414 | US 521 – Sumter | Northern terminus |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus |||||

### Kershaw truck route

U.S. Route 521 Truck (US 521 Truck) is a truck route of US 521 that exists entirely within the northern part of the town of Kershaw. It connects US 521 (North Matson Street) with US 521 Business (US 521 Bus.) and US 601 Bus. (North Hampton Street). It is completely concurrent with US 601, South Carolina Highway 157 Truck (SC 157 Truck), and SC 341 Truck. It is known as Hilton Street. There is no signs on US 521 or US 521 Bus./US 601 Bus. There is one sign just south of its northern terminus.

### Kershaw connector route

U.S. Route 521 Connector (US 521 Conn.) is a 0.060-mile (0.097 km) connector route of US 521 that serves to connect US 521 Business (US 521 Bus.) with US 521 (North Matson Street / Kershaw–Camden Highway) north of Kershaw. It is unnamed and is an unsigned highway.

### Lancaster business loop

U.S. Route 521 Business (US 521 Bus.) is a 3.870-mile (6.228 km) business route of US 521 that travels through downtown Lancaster, via Market Street and Main Street. It follows the old US 521 mainline route. At some point, it was relocated to Market Street until the intersection with Barr Street, where it turned left and then right onto Main Street.
The entire route is in Lancaster, Lancaster County.
| mi | km | Destinations | Notes |
| 0.000 | 0.000 | US 521 (Kershaw-Camden Highway/Lancaster Bypass) – Heath Springs, Kershaw | Southern terminus |
| 1.440 | 2.317 | Camden–Kershaw Highway north | Southern terminus of Camden–Kershaw Highway; former US 521 Bus. north |
| 1.660 | 2.672 | SC 200 west (Great Falls Highway) – Great Falls | Southern end of SC 200 concurrency |
| 2.270 | 3.653 | SC 903 south (Chesterfield Avenue) – McBee | Northern terminus of SC 903 |
| 2.380 | 3.830 | SC 9 Bus. south (East Arch Street) – Pageland | Southern end of SC 9 Bus. concurrency |
| 2.650 | 4.265 | SC 9 Bus. north (East Meeting Street) – Chester, Charlotte | Northern end of SC 9 Bus. concurrency |
| 2.900 | 4.667 | West Barr Street west / North Main Street south | Former US 521 Bus. south; US 521 Bus./SC 200 turns right. |
| 3.680 | 5.922 | SC 200 east (Liberty Hill Road) to US 521 south – Pageland, Monroe | Northern end of SC 200 concurrency |
| 3.870 | 6.228 | US 521 north / SC 9 (Lancaster Bypass) – Chester, Rock Hill, Charlotte, Chesterfield, Chester, Myrtle Beach, Andrew Jackson State Park | Northern terminus; interchange |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus ||||

## Former special routes
### Sumter connector

U.S. Route 521 Connector (US 521) was a 4.7 miles (7.6 km) connector route that went east around Sumter along Guignard Drive, connecting to US 15, in the southern end of Sumter. This connector became part of the main route sometime before 2009.

### Lancaster Bypass

U.S. Route 521 Bypass (US 521 Byp.) was the bypass around downtown Lancaster, until the mainline was realigned in 1965, and the former route was converted into US 521 Business (US 521 Bus.).