Porcupine is a census-designated place (CDP) in Oglala Lakota County, South Dakota, United States. The population was 925 at the 2020 census.

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.