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.