The Presidio of San Francisco (originally, El Presidio Real de San Francisco or Royal Presidio of San Francisco) is a park on the northern tip of the San Francisco Peninsula in the City and County of San Francisco. It is operated by the National Park Service of the United States as a part of the Golden Gate National Recreation Area. The largest area, the "Main Post," is managed by the Presidio Trust, a congressionally chartered nonprofit organization. The park is characterized by many wooded areas, hills, and scenic vistas overlooking the San Francisco Bay.

The Presidio was recognized by Congress as a National Historic Landmark District, the highest historic designation that can be given in the U.S. This designation is given to a collection of structures and the surrounding lands that have nationally important historical integrity. The Presidio Trust Act calls for "preservation of the cultural and historic integrity of the Presidio for public use." The Act also requires that the Presidio Trust be financially self-sufficient by 2013. These imperatives have resulted in numerous conflicts between the need to maximize income by leasing historic buildings, and permitting public use despite most structures being rented privately. Further differences have arisen from the divergent needs of preserving the integrity of the National Historic Landmark District in the face of new construction, competing pressures for natural habitat restoration, and requirements for commercial purposes that impede public access. As of 2007, there was only a rudimentary visitors' center to orient visitors to the Presidio's history.