State Line was located on the Mobile and Ohio Railroad, built through Mississippi in the 1850s.

U.S. Route 45 passes through the northeast corner of the town, leading northwest 20 miles (32 km) to Waynesboro, the Wayne County seat, and southeast 63 miles (101 km) to Mobile, Alabama.

Mississippi Highway 57 passes through the east side of State Line, leading south 23 miles (37 km) to Leakesville, the Greene County seat.

Mississippi Highway 42 passes through the center of State Line as St. Peter Street, leading west 53 miles (85 km) to Hattiesburg.

[8] As of the 2020 United States census, there were 452 people, 250 households, and 176 families residing in the town.

The racial makeup of the town was 42.70% White, 56.94% African American, and 0.36% from two or more races.