Portions of Chesterfield are located in the floodplain of the Missouri River, now known as Chesterfield Valley, formerly as Gumbo Flats. Here several small creeks empty into the Missouri River (Caulks Creek and Bonhomme Creek). This area was submerged during the Great Flood of 1993; higher levees built since then have led to extensive commercial development in the valley. Chesterfield Valley is the location of Spirit of St. Louis Airport, used for corporate aviation, as well as the longest outdoor strip mall in America.