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.