South Carolina Highway 125

SC 125 is the only highway through which the public is allowed to travel through the Savannah River Site. However, for the 17.3 miles (27.8 km) stretch it travels through SRS, vehicles are prohibited from stopping except for emergencies. Mile-markers going north to south help travelers count the miles before they are out of the restricted area. The highway is flanked with trees and fences and, on occasion, defunct roads crossing the highway with gates restricting access; the biggest being the former SC 64 interchange near mile marker 8.[5] Though the highway is maintained by SCDOT, it is patrolled by federal security; the speed limit throughout is 55 miles per hour (89 km/h).

Prior to 2006, checkpoints were located at both ends of SC 125. When arriving at the entrance checkpoint, drivers would receive a pass and may also have their car searched at that time. Drivers were required to return the pass at the exit checkpoint; for those that drove too quickly to the other end would be issued a speeding ticket. Drivers that failed to either return the pass or arrive later than expected could be withheld for further questioning by authorities. After 2006, the checkpoints were removed along route, though checkpoints still exist at some roads that go deeper into the Savannah River Site.

South Carolina Highway 125 Connector (SC 125 Conn.) is a 0.772-mile-long (1.242 km) connector route that is unsigned.[7] It travels completely within the southwestern part of Aiken County. Its entire length is within the southern part of North Augusta.

The connector begins at an intersection with the southbound lanes of U.S. Route 1 (US 1), which is also the westbound lanes of US 78/US 278 (Jefferson Davis Highway). There is no access from Jefferson Davis Highway north to East Buena Vista Avenue or vice versa. SC 125 Conn. travels to the northwest and immediately curves to the west-northwest. At an intersection with US 25/SC 121 (East Martintown Road), it turns right onto those highways and travels concurrently with them to the north-northwest. It takes the next left, onto another segment of East Buena Vista Avenue, and travels to the west-southwest. Immediately, it curves to the northwest. Just after an intersection with the western terminus of Floyd Street, it resumes its west-northwest direction. It then meets its northern terminus, an intersection with the SC 125 mainline (known as East Buena Vista Avenue west of here and Atomic Road north of here).

The entire route is in North Augusta, Aiken County.

mi[6]	km	Destinations	Notes
0.000	0.000	Jefferson Davis Highway south (US 1 south / US 78 west / US 278 west)	No access from US 1 north/US 78 east/US 278 east to SC 125 Truck or vice versa; southern terminus
0.190	0.306	East Martintown Road south (US 25 south / SC 121 south)	Southern end of US 25/SC 121 concurrency
0.300	0.483	East Martintown Road north (US 25 north / SC 121 north)	Northern end of US 25/SC 121 concurrency
0.772	1.242	SC 125 (East Buena Vista Avenue west / Atomic Road east)	Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access

South Carolina Highway 125 Truck (SC 125 Truck) is a 1.730-mile-long (2.784 km) truck route of SC 125 that travels completely within the southwestern part of Aiken County. Its entire length is within the southern part of North Augusta.

The truck route begins at an intersection with US 25/SC 121 (East Martintown Road). This intersection is also the eastern terminus of SC 230. US 25, SC 121, SC 125 Truck, and SC 230 travel concurrently to the northwest. The roadway is a retail corridor with many businesses along its path. At an intersection with Knox Avenue, US 25/SC 121 split off to the north, while SC 125 Truck and SC 230 continue to the northwest on East Martintown Road. Approximately 0.5 miles (0.80 km) later, they intersect US 25 Business (US 25 Bus.; Georgia Avenue). Here, SC 125 Truck turns left onto the business route to the southwest, while SC 230 continues to the northwest. At the southern terminus of Carolina Avenue, US 25 Bus. and SC 125 Truck curves to the south-southwest. At an intersection with the northern terminus of SC 125 (Buena Vista Avenue), the truck route ends, and US 25 Bus. continues to the south-southwest.[11]

The entire route is in North Augusta, Aiken County.

mi[8][9][10]	km	Destinations	Notes
0.000	0.000	US 25 south / SC 121 south / SC 230 begins (East Martintown Road south) to US 1 / US 78 / US 278 – Augusta SC 125 (Atomic Road) – Savannah River Site, North Augusta	Southern end of US 25/SC 121 and SC 230 concurrencies; southern terminus of SC 125 Truck; eastern terminus of SC 230
0.430	0.692	US 25 north / SC 121 north (Knox Avenue) – Edgefield	Northern end of US 25/SC 121 concurrency
0.970	1.561	US 25 Bus. north (Georgia Avenue north) – Newberry, Greenville SC 230 west (East Martintown Road) to I-20 – Clarks Hill, McCormick	Northern end of SC 230 concurrency; southern end of US 25 Bus. concurrency
1.730	2.784	US 25 Bus. south (Georgia Avenue south) SC 125 south (Buena Vista Avenue east) / Buena Vista Avenue west	Northern end of US 25 Bus. concurrency; northern terminus of SC 125 and SC 125 Truck
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus