SD 48 begins at a diamond interchange on I‑29 Exit 31, approximately 44 miles (71 km) south of Sioux Falls.

[citation needed] Two miles (3.2 km) east of the CR 1C intersection, SD 48 passes through the town of Spink.

[4] East of Spink, SD 48 gently curves to the north as it descends a rolling hill towards Brule Creek.

After crossing the stream, the highway ascends, bending back to the south to resume its due east course.

[6][1] For the remainder of the route, the road gradually S-curves southwest into the Big Sioux River valley.