40th Infantry Division (United States)

40th Infantry Division (United States)
Unit name	40th Infantry Division
Caption	Shoulder sleeve insignia of the 40th Infantry Division
Dates	1917–1919, 1926–1946, 1947–present
Country	United States
Branch	United States Army
Type	Infantry
Size	Division
Command structure	California Army National Guard
Garrison	Los Alamitos
Nickname	"Sunshine Division" (World War I), "Fighting Fortieth"
Battles	World War I, World War II, Korean War
Notable commanders	John H. Church, Ralph H. Van Deman
Identification symbol	75px
Identification symbol label	Distinctive unit insignia

40th Infantry Division (United States). The 40th Infantry Division is a modular division of the United States Army National Guard. Primarily composed of units from the California Army National Guard, it has served in both World Wars and the Korean War. Currently headquartered at Los Alamitos Joint Forces Training Base, it is a key component of the Army National Guard's operational force.

History

The division was originally constituted in 1917 from National Guard units of California, Arizona, Colorado, Nevada, New Mexico, and Utah, earning the nickname "Sunshine Division" during its stateside service in World War I. It was demobilized in 1919 before being reconstituted in the interwar period. The unit was inducted into federal service in March 1941, training at Camp San Luis Obispo before deployment to the Pacific Theater of Operations. Following distinguished service in World War II and the Korean War, it was reorganized as part of the Army National Guard's modernization, participating in numerous domestic and overseas missions.

Organization

The division's current structure follows the United States Army's modular design, capable of commanding multiple brigade combat teams. Its core formations include the Division Headquarters and Headquarters Battalion at Los Alamitos Joint Forces Training Base. Historically, its major subordinate units included the 79th Infantry Brigade Combat Team, the 81st Stryker Brigade Combat Team, and the 40th Combat Aviation Brigade, though its exact order of battle has evolved through various reorganizations like the Pentomic structure and ROAD.

World War II service

After training, the division deployed to Guadalcanal in 1942 for security duties before engaging in combat. It saw extensive action in the Philippines campaign (1944–1945), participating in the Battle of Luzon, including operations to recapture Fort Stotsenburg and Clark Field. The division later fought in the Battle of Zigzag Pass and was instrumental in the liberation of Bataan and Corregidor. Its final campaigns included the Invasion of Palawan and the Battle of Mindanao, contributing significantly to the defeat of Imperial Japanese Army forces before occupying Japan after Victory over Japan Day.

Post-World War II and Cold War era

Following occupation duty in Japan and South Korea, the division was inactivated in 1946 but reformed in the California Army National Guard in 1947. During the Korean War, it was activated and deployed to Japan, later relieving the 24th Infantry Division on the front lines in 1952, where it fought in sectors like the Heartbreak Ridge area. Throughout the Cold War, it trained extensively, with elements participating in Operation Desert Storm and, later, the Global War on Terrorism, including deployments to Kosovo, Iraq, and Afghanistan.

Commanders

Notable commanders include Major General Ralph H. Van Deman, known as the "father of American military intelligence," who led the division during its stateside service in World War I. In World War II, Major General Rapp Brush commanded the division through its campaigns in the Philippines. During the Korean War, Major General John H. Church, who had previously served on the staff of General Douglas MacArthur, led the division in combat on the Korean Peninsula.

Insignia and nicknames

The division's shoulder sleeve insignia is a blue diamond, representing its original constituent states, with a golden sun symbolizing its "Sunshine Division" moniker from World War I. Its official nickname is the "Fighting Fortieth," a title earned through its combat performance in the Pacific Theater and Korean War. The distinctive unit insignia was approved in 1926, featuring a cactus and a rattlesnake, emblematic of the Southwestern United States.

Category:Infantry divisions of the United States Army Category:Military units and formations established in 1917 Category:United States Army divisions of World War I Category:United States Army divisions of World War II