South Dakota's 4th legislative district is one of 35 districts in the South Dakota Legislature. Each district is represented by 1 senator and 2 representatives. In the Senate, it has been represented by Republican John Wiik since 2017. In the House, it has been represented by Republicans Kent Roe and Dylan C. Jordan since 2025. It was previously represented by Republicans Stephanie Sauder since 2023 and Fred Deutsch since 2019.
The district is located in northeastern South Dakota, containing Clark, Codington, Deuel, Grant, Hamlin, and Roberts county. The district completely surrounds the 5th district in Watertown.
South Dakota legislators are elected to two-year terms, with each permitted to serve a maximum of four consecutive two-year terms. Elections are held every even-numbered year.