Pennington County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 100,948, making it the second-most populous county in South Dakota. Its county seat is Rapid City. It was created in 1875.
Pennington County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 100,948, making it the second-most populous county in South Dakota. Its county seat is Rapid City. It was created in 1875.