Oglala Lakota County, known as Shannon County until May 2015, is a county located in the U.S. state of South Dakota. The population was 13,586 at the 2010 census. Oglala Lakota County does not have its own county seat. Instead, Hot Springs in neighboring Fall River County serves as its administrative center. The county was created as a part of the Dakota Territory in 1875, although it remains unorganized.