Castle Airport (IATA: MER, ICAO: KMER, FAA LID: MER) is a public use airport located seven nautical miles (13 km) northwest of the Central business district of Merced, a city in Merced County, California, United States. It is operated by the Merced County Department of Commerce, Aviation, and Economic Development.
The airport is located at the former Castle Air Force Base which closed in 1995. This land is owned jointly by the city of Merced, city of Atwater and the county of Merced. Until 2007 this land was administered by the JPA or Joint Powers Administration.