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 and Moreno Valley. It is the home to the Air Force Reserve Command's 4th Air Force (4 AF) Headquarters and the host 452d Air Mobility Wing (452 AMW), the largest air mobility wing of the 4th 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 and the California Air National Guard.