William H. Bonney (born William Henry McCarty, Jr. c. November 23, 1859 – c. July 14, 1881), better known as Billy the Kid but also known as Henry Antrim, was a 19th-century American gunman who participated in the Lincoln County War and became a frontier outlaw in the American Old West. According to legend, he killed 21 men,[2] but it is generally believed that he killed between four and nine.[2] He killed his first man at 18.