Mountain Plains, South Dakota
Mountain Plains is an unincorporated area and census-designated place in Lawrence County, South Dakota. It had a population of 327 at the 2020 census. The community covers about 1.59 square miles (4.13 square kilometers), all land, and sits at an elevation of 4,278 feet. It lies in the northern part of the county on the northern edge of the Black Hills, just north of the city of Spearfish. U.S. Route 14A runs along the eastern edge, following the Spearfish Creek canyon. Mountain Plains is part of Spearfish School District 40-2. The ZIP code is 57783 (shared with Spearfish) and the area code is 605. The area observes Mountain Time (UTC-7, UTC-6 in summer).
This page was last edited on 2 February 2026, at 05:23 (CET).