Don Edwards San Francisco Bay National Wildlife Refuge, the first urban National Wildlife Refuge established in the United States, is dedicated to preserving and enhancing wildlife habitat, protecting migratory birds, protecting threatened and endangered species, and providing opportunities for wildlife-oriented recreation and nature study for the surrounding communities.
As of 2004, the Refuge spans 30,000 acres (120 km2) of open bay, salt pond, salt marsh, mudflat, upland and vernal pool habitats located throughout south San Francisco Bay. Located along the Pacific Flyway, the Refuge hosts over 280 species of birds each year. Millions of shorebirds and waterfowl stop to refuel at the Refuge during the spring and fall migration. In addition to its seasonal visitors, the Refuge provides critical habitat to resident species like the endangered California clapper rail and salt marsh harvest mouse. Today, hundreds of thousands of people visit the Refuge each year to enjoy its diverse wildlife and habitats.