Mouwembleem 40th Infantry Division (Sleeve patch 40th Infantry Division)

The 40th Infantry Division (Mechanized) ("Sunshine Division") is a modular division of the United States Army. Following the army's modularization the division has become a four brigade combat team division with National Guardsmen from throughout the Pacific/Western United States and Oceania. Its Division Headquarters is located at Los Alamitos Joint Forces Training Base in Los Alamitos, California.

After seeing service in World War I as a depot division, it was reorganised as the National Guard division for California, Nevada, and Utah, before seeing service in the Pacific Theatre of World War II. Later, the division served in Korea and some of its units were designated for Vietnam.

The 40th Infantry Division was activated for World War II on 3 March 1941. It was at the time a National Guard division from the California, Nevada Army National Guard, and Utah Army National Guards. In February 1942, the 40th Infantry Division was reorganized from a 'square', two-brigade, four-regiment division to a three-regiment division without any intermediate brigade headquarters. Thus the 79th and 80th Infantry Brigade were inactivated.

It departed for overseas service on 23 August 1942. The Division's first overseas assignment was the defense of the outer Hawaiian Islands, where it arrived in September 1942. Training continued as defensive positions were improved and maintained. In July 1943, the division was concentrated on Oahu, and relieved the 24th Infantry Division of the defense of the North Sector. Relieved of the North Sector in October 1943, the 40th entered upon a period of intensive amphibious and jungle training. On 20 December 1943, the first units left for Guadalcanal, and by mid-January 1944, movement was completed, and the division prepared for its first combat assignment. On 24 April 1944, it left Guadalcanal for New Britain. The regiments of the division took positions at Talasea on the northern side of the island, at Arawe on the southern side, and at near the western end. Neutralization of the enemy was effected by patrols. No major battle was fought. Heavy rain and mud were constant problems.

The 40th was relieved of missions on New Britain, 27 November, and began training for the Luzon landing. Sailing from Borgen Bay on 9 December 1944, the division made an assault landing atLingayen, Luzon, under command of XIV Corps, on 9 January 1945. Seizing Lingayen airfield, the division occupied Bolinao Peninsula and San Miguel, and advanced toward Manila, running into heavy fighting in the Fort Stotsenburg area and the Bambam Hills. Snake Hill and Storm King Mountain were taken in February and the 40th was relieved, 2 March. Leaving Luzon on 15 March 1945 to cut behind the Japanese, the division landed on Panay Island on the 18th and knocked out Japanese resistance within ten days, seizing airfields at Santa Barbara andMandurriao. On 29 March, it landed at Pulupandan, Negros Occidental, advanced through Bacolod City toward Talisay, which it secured by 2 April 1945. After mopping up on Negros Island, the division returned to Panay in June and July 1945. In September 1945, the division moved to Korea for occupation duty.

The division returned to the U.S. on 7 April 1946 and was reportedly inactivated the same day. Its casualties during the war included 614 Killed in Action, 2,407 Wounded in Action, and 134 Died of Wounds.