March Air Reserve Base (IATA: RIV, ICAO: KRIV, FAA LID: RIV) (March ARB), previously known as March Air Force Base (March AFB), is located in Riverside County, California, between the cities of Riverside, Moreno Valley, and Perris. It is the home to the Air Force Reserve Command's Fourth Air Force (4 AF) Headquarters and the host of the 452nd Air Mobility Wing (452 AMW), the largest air mobility wing of the Fourth Air Force. In addition to multiple units of the Air Force Reserve Command supporting Air Mobility Command, Air Combat Command and Pacific Air Forces, March ARB is also home to units from the Army Reserve, Navy Reserve, Marine Corps Reserve, California Air National Guard and the California Army National Guard. For almost 50 years, March AFB was a Strategic Air Command base during the Cold War. The facility covers 2,075 acres (840 hectares) of land.