Brookings County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 34,375, making it the fifth most populous county in South Dakota. Its county seat is Brookings. The county was created in 1862 and organized in 1871.

Brookings is a city in and the county seat of Brookings County, South Dakota, United States. Brookings is South Dakota's fourth most populous city, with a population of 23,377 at the 2020 census. It is home to South Dakota State University, the state's largest institution of higher education. Also in Brookings are the South Dakota Art Museum, the Children's Museum of South Dakota, the annual Brookings Summer Arts Festival, and the headquarters of several manufacturing companies and agricultural operations.