De Soto is a city in Jefferson County, Missouri, United States. The population was 6,477 at the estimated 2008 census. The town was organized in 1857 and is named for the explorer Hernando De Soto, who claimed the Louisiana Territory for Spain. De Soto was the city closest to the mean center of U.S. population in 1980. The city celebrated its Bicentennial in 2003. The city made national news on and after May 6, 2003, when straightline winds/tornado struck.