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, but it is generally believed that he killed between four and nine. He killed his first man at 18.