SD 30 begins at an intersection with County Road 77 (CR 77; 471st Avenue) and the eastern terminus of CR 6 (204th Street) approximately 7 miles (11 km) west of White, in the north-central part of Brookings County.

An intersection with 203A Street leads to the eastern part of White, as well as the city park.

Jues west of the southern terminus of CR 29 (485th Avenue), it crosses over Deer Creek.

Approximately 3,300 feet (1,000 m) after this intersection, SD 30 meets its eastern terminus, an intersection with the southern terminus of 487B Avenue at the Minnesota state line, northeast of Bushnell.

Here, the roadway continues to the east as Minnesota State Highway 19 (MN 19).

The western segment extended from SD 25, north of De Smet, to U.S. Route 81 (US 81), south of Lake Poinsett.

The eastern segment extended from US 77, west of White, to the Minnesota state line.