AC St. Louis was an American professional soccer team based in St. Louis, Missouri, United States. Founded in December 2009, the team played its first and only season the next year in the NASL Conference of the temporary USSF D2 Pro League, the second tier of the American Soccer Pyramid. With plans to join the new North American Soccer League the following season, the club folded in January 2011 under unmanageable financial strain.