Question: Sacramento Mather Airport is located on the site of a former air force base, located 12 mi east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, California, which was closed in what year?
Sentence (from "Sacramento Mather Airport"): Sacramento Mather Airport (IATA: MHR, ICAO: KMHR, FAA LID: MHR) , also known as simply Mather Airport, is a county-owned public-use airport located 10 nautical miles (19 km) east of the central business district of Sacramento, in Sacramento County, California, United States.
Relevant evidence: Yes