Oglala Lakota County is a county in southwestern South Dakota, United States. As of the 2020 census, the population was 13,672. Oglala Lakota County does not have a functioning county seat; 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. Its largest community is Pine Ridge.

A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equivalent term, shire town, is used in the U.S. state of Vermont and in several other English-speaking jurisdictions. County towns usually serve a similar function in Ireland, Jamaica, and the United Kingdom.