2 Islands to Explore in San Francisco County

Developed with facilities for a lighthouse, a military fortification, a military prison, and a federal prison that seized operations in the 1960s. Today the small island is open for tours.

Angel Island is the largest natural island in the San Francisco Bay, offers some of the best views of the surrounding Bay Area. It has been used by humans for a variety of purposes, including seasonal hunting and gathering by indigenous peoples, water and timber supply for European ships, ranching by Mexicans, United States military installations, a United States Public Health Service Quarantine Station, and a U.S. Bureau of Immigration inspection and detention facility.