Simon Bolivar Buckner, Jr. (July 18, 1886 – June 18, 1945) was a lieutenant general in the United States Army during World War II. He served in the Pacific Theater of Operations and commanded the defenses of Alaska early in the war. Following that assignment, he was promoted to command the 10th Army, which conducted the amphibious assault on the Japanese island of Okinawa on April 1, 1945. He was killed during the closing days of the Battle of Okinawa by enemy artillery fire, making him the highest-ranking U.S. military officer to have been lost to enemy fire during World War II.