Clayton, MO

Clayton was organized in 1877 and named for Ralph Clayton, who donated the land for the St. Louis County courthouse. The city borders the independent city of St. Louis and serves as the county seat; 17,355 people lived there in 2020. Downtown contains the county government campus, council, courts, justice center, and police headquarters while also functioning as a primary business district for the St. Louis region. Concordia Seminary stands near DeMun. Washington University’s South 40 student-housing area occupies part of eastern Clayton, and its West Campus has university offices downtown. Oak Knoll Park previously housed the St. Louis area’s Academy of Science before that institution moved to Forest Park and became the St. Louis Science Center. Fontbonne University closed after the 2025 academic year.