The final campaign the division would take part in during World War II would be the Battle of Okinawa. The strategic importance of Okinawa was that it provided a fleet anchorage, troop staging areas, and airfields in close proximity to Japan. The division landed on 1 April 1945 as part of the III Amphibious Corps. Its initial mission was, fighting alongside the 6th Marine Division, to clear the northern half of the island – that they were able to do expeditiously. The Army's XXIV Corps met much stiffer resistance in the south, and on 1 May 1945 the Marine division was moved south where it relieved the Army's 27th Infantry Division. The division was in heavy fighting on Okinawa until 22 June 1945, when the island was declared secure. The 1st Marine Division slugged it out with the Japanese 32nd Army at such places as Dakeshi Ridge, Wana Ridge, "Sugarloaf Hill" and Shuri Castle. Fighting on Okinawa cost the division 1,655 killed in action.