Mitchel Air Force Base, also known as Mitchel Field, was a United States Air Force base located on the Hempstead Plains of Long Island, New York, United States. Established in 1918 as Hazelhurst Aviation Field #2, the facility was renamed later that year as Mitchel Field in honor of former New York City Mayor John Purroy Mitchel, who was killed while training for the Air Service in Louisiana.

The Hempstead Plains is a region of central Long Island, in what is now Nassau County, in New York State. It was once an open expanse of native grassland estimated to once extend to about 60,000 acres. It was separated from the North Shore of Long Island by the Harbor Hill Moraine, later approximately Route 25. The modern Hempstead Turnpike approximately traces the separation of the plain from the South Shore of Long Island. The east–west extent was from somewhat west of the modern Queens, New York City border to slightly beyond the Suffolk County border.