The history of the 4th Tank Battalion is an active one and typifies the role of the Marine Corps Reserve.
First formed in World War II, it was composed, with the exception of two officers, entirely of reserve personnel. It participated during the campaigns for Kwajalein, Saipan, Tinian, and on Iwo Jima. Of particular note, it holds distinction as the first unit to capture Japanese mandated territory in the Pacific during the war.
Late in 1946, a group of World War II veterans began meeting at the Marine Corps Recruit Depot on a volunteer basis. This established foundation for the first organized Marine Corps Reserve unit in San Diego. Officially designated as the 11th Tank Battalion in 1947, a headquarters staff and a tank company formed.
In July, 1950, the unit activated for the Korean Conflict and San Diego reservists formed the nucleus of Company B, 1st Tank Battalion, at Camp Pendleton. Serving with distinction, this unit participated in the landings at Inchon and Wonsan, fighting to Hagaru and Koto-Ri. Company B remained in the KTO through the armistice.
During May 1952, the unit relocated to MCRD San Diego and reflagged as 1st Tank Battalion. In 1958, the battalion moved to Camp Elliot and was re-designated 4th Tank Battalion, Force Troops, Fleet Marine Force, USMCR during July 1962.
Today, 4th Tank Battalion is the only reserve tank battalion in the Marine Corps. Six companies strong, it is also the largest tank battalion in the U.S. Military. Spanning the continental United States, units are located in San Diego, California; Yakima, Washington; Boise, Idaho; 29 Palms, California; Fort Knox, Kentucky; Camp Lejeune, North Carolina; and in Hialeah, Florida.
The 4th Tank Battalion motto is "53 days." When Marine reservists were activated for the Korean Conflict, it was just 53 days until they participated in their first combat action - the landing at Inchon during September 1950. Between November 1990 and January 1991, 4th Tank Battalion was mobilized in support of Operation Desert Shield/Storm. Elements of the battalion were "in country" and combat ready within 32 days of activation. A large portion of the Battalion, over the previous five years, activated in support of Operation Iraqi Freedom; several units on more than one occasion. Elements continue service in support of the Global War on Terrorism to this day.