St. Louis County has not included the City of St. Louis since 1877, after city residents voted to separate and become an independent city.
Missouri became part of the United States on October 1, 1804 • 8 years later on October 1, 1812, the District of St. Louis was renamed St. Louis County • Clayton County is the County Seat.
St. Louis County is also home to the City of Ferguson. Founded in 1894 and home to the Challenger Learning Center – St. Louis, which provides a space education program.