The San Francisco Bay Discovery Site, a National Historic Landmark, marks the site on top of Sweeney Ridge, where, in 1769, members of Gaspar de Portolo's overland exploration expedition first saw the San Francisco Bay. Following this momentous discovery by the Spaniards, a presidio and two missions were established in what is now San Francisco.
The San Francisco Bay Discovery Site is located about twenty five minutes south of San Francisco, between San Bruno and Pacifica. To get to the site from Pacifica, Sweeney Ridge trailheads are located at Sheldance Nursery off of Highway 1, and at the east end of Fassler Avenue. From San Bruno, trails start from the west end of Sneath Lane off of Hwy 35 (Skyline Blvd) and from Skyline College Parking Lot #2. Sweeney Ridge is part of the National Park Service's Golden Gate National Recreation Area.