South St. Paul is a city in Dakota County, Minnesota, United States, immediately south and southeast of St. Paul and east of West St. Paul. The population was 20,759 at the 2020 census. The town was a major meat-packing location, and many residents are descended from immigrants of Southern European and Eastern European heritage, who came to work in the meat-packing plants in the early twentieth century. A post office called "South St. Paul" has been in operation since 1888.