Johnsonville is located in southeastern Florence County at 33°49′4″N 79°26′54″W (33.817802, -79.448288).
The center of town is 1.5 miles (2.4 km) south of the crossing of the Lynches River by South Carolina Highways 41 and 51.
The combined highways lead north 4 miles (6 km) to U.S. Route 378 at Kingsburg and south 5 miles (8 km) to Hemingway.

South Carolina Highway 341 passes through the center of town as Broadway Street, leading west 20 miles (32 km) to Lake City.
Florence, the county seat, is 35 miles (56 km) to the northwest, while Myrtle Beach is 45 miles (72 km) to the east.

According to the United States Census Bureau, the city has a total area of 2.1 square miles (5.4 km²), of which 0.03 square miles (0.07 km²), or 1.36%, is water.

The city of Johnsonville is located only a few miles from The Johnsonville Impact Crater, a circular geophysical feature that has been interpreted by some scientists as an impact crater, situated at the junction of Lynches River and the Pee Dee River in South Carolina.
Snows Island, at that point, is believed to be the upthrust of the center after the impact.
This eight-mile-wide crater is not well defined at the surface and was discovered by magnetic anomalies and supported by the study of well drilling cores.
Supposed impact breccia was found in these cores.
Johnsonville is located in southeastern Florence County at 33°49′4″N 79°26′54″W (33.817802, -79.448288). The center of town is 1.5 miles (2.4 km) south of the crossing of the Lynches River by South Carolina Highways 41 and 51. The combined highways lead north 4 miles (6 km) to U.S. Route 378 at Kingsburg and south 5 miles (8 km) to Hemingway.
South Carolina Highway 341 passes through the center of town as Broadway Street, leading west 20 miles (32 km) to Lake City. Florence, the county seat, is 35 miles (56 km) to the northwest, while Myrtle Beach is 45 miles (72 km) to the east.
According to the United States Census Bureau, the city has a total area of 2.1 square miles (5.4 km²), of which 0.03 square miles (0.07 km²), or 1.36%, is water.
The city of Johnsonville is located only a few miles from The Johnsonville Impact Crater, a circular geophysical feature that has been interpreted by some scientists as an impact crater, situated at the junction of Lynches River and the Pee Dee River in South Carolina. Snows Island, at that point, is believed to be the upthrust of the center after the impact. This eight-mile-wide crater is not well defined at the surface and was discovered by magnetic anomalies and supported by the study of well drilling cores. Supposed impact breccia was found in these cores.
Johnsonville, South Carolina