The 5th Marine Division was a United States Marine Corps infantry division which was activated on November 11, 1943 (officially activated on January 21, 1944) at Camp Pendleton, California during World War II. The 5th Division saw its first combat action during the Battle of Iwo Jima in 1945 where it sustained the highest number of casualties of the three Marine divisions of the V Amphibious Corps (invasion force). The 5th Division was to be part of the planned invasion of the Japan homeland before Japan surrendered. Assault troops of the 5th Division were included in the Presidential Unit Citation awarded to the V Amphibious Corps for extraordinary heroism on Iwo Jima from February 19 to 28, 1945. The 5th Division was deactivated on February 5, 1946.