USS Decatur was a sloop-of-war in the United States Navy during the mid-19th century. She was commissioned to protect American interests in the South Atlantic Ocean, including the interception of ships involved in the African slave trade. Decatur served in both the Mexican-American War and the American Civil War. The sloop-of-war was named in honor of Commodore Stephen Decatur (1779–1820), one of the United States Navy's greatest heroes and leaders of the first two decades of the 19th Century.