John Singleton Mosby (December 6, 1833 – May 30, 1916), also known by his nickname "Gray Ghost", was an American military officer who was a Confederate cavalry commander in the American Civil War. His command, the 43rd Battalion, Virginia Cavalry (known as Mosby's Rangers or Mosby's Raiders) was a partisan ranger unit noted for its lightning-quick raids and its ability to elude Union Army pursuers and blend in with local farmers and townsmen. The area of northern central Virginia in which Mosby operated with impunity became known as Mosby's Confederacy.
After the Civil War, Mosby became a Republican and worked as an attorney, supporting his former enemy's commander, U.S. President Ulysses S. Grant. He also served as the American consul to Hong Kong and in the U.S. Department of Justice.
In 1992, Mosby was among the first group of men inducted into the United States Army Ranger Hall of fame. In June 2023, the Fort Benning garrison commander ordered his name to be removed from the hall of fame as well as the National Ranger Memorial along with three other rangers that included William Quantrill, George Bowman and Jackson Bowman.