Richardson Bay (originally Richardson's Bay) is a shallow, ecologically rich arm of San Francisco Bay, managed under a Joint Powers Agency of four Northern California cities. The 911-acre (369 ha) Richardson Bay Sanctuary was acquired in the early 1960s by the National Audubon Society. The bay was named for William A. Richardson, early 19th century sea captain and builder in San Francisco.

Richardson Bay is one of the most pristine estuaries on the Pacific Coast in spite of its urbanized periphery, since it supports extensive eelgrass areas and sizable undisturbed intertidal habitats. It is a feeding and resting area for a panoply of estuarine and pelagic birds, while its associated marshes and littoral zones support a variety of animal and plant life. Richardson Bay has been designated as an Important Bird Area (IBA), based upon its large number of annual bird visitors and residents, its sightings of California clapper rail and its strategic location in the flyway. The bay's waters are subject to a "no discharge" rule to protect the elaborate and fragile ecosystems present, including a complex fishery, diverse mollusk populations and even marine mammals such as the harbor seal. (more...)