Crissy Field, a former U.S. Army airfield, is now part of the Golden Gate National Recreation Area in San Francisco, California, United States. Historically part of the Presidio of San Francisco, Crissy Field closed as an airfield after 1974. Under Army control, the site was affected by dumping of hazardous materials. The National Park Service took control of the area in 1994 and cleaned it up, and in 2001 the Crissy Field Center opened to the public. While most buildings have been preserved as they were in the 1920s, some have been transformed into offices, retail space, and residences.
The land Crissy Field resides on is an ancient 130-acre (53 ha) salt marsh and estuary. Prior to European settlement, the Ohlone people used the area for harvesting shellfish and fish. They also lived in seasonal camps in the area, leaving behind shell middens in the archaeological record. The Spanish arrived in 1776 and called the area El Presidio. They began to use the area for livestock grazing and agriculture. The 127-acre marsh site was filled in during the 1870s. This alteration was finished in time for the 1915 Panama Pacific International Exposition. The U.S. Army took control of the Presidio in 1846, using the tidal wetland as a wasteland for dumping and draining. After filling in the marshlands, the Army covered over it and created an aerodrome.
During World War I the Army constructed numerous temporary buildings on the site of the 1915 Panama–Pacific International Exposition at the Presidio of San Francisco and linked it to Fort Mason with a rail spur. In July 1918 Congress passed Public Law 189 to establish eight "air coast defense stations" and appropriated $1,500,000 for the construction of one of them at the Presidio, to protect San Francisco Bay. In June 1919 the Army assigned Colonel Henry H. Arnold of the Air Service as Air Officer, Western Department, and directed him to convene a board of four officers to select the site. The board chose the former exposition site as much for its sheltered beach to protect seaplane operations as the fact that the infield of its racetrack was already in use as an aviation field. Although the wartime appropriations were reduced by the end of the war, demolition of buildings posing a landing hazard began in the fall of 1919.