Puget Sound only Puget Sound proper but also for waters to the north, such as Bellingham Bay and the San Juan Islands region. The term "Puget Sound" is used not just for the body of water but also the Puget Sound region centered on the sound. Major cities on the sound include Seattle, Tacoma, Olympia, and Everett, Washington. Puget Sound is also the third largest estuary in the United States, after Chesapeake Bay in Maryland and Virginia, and San Francisco Bay in northern California. In 1792 George Vancouver gave the name "Puget's Sound" to the waters south of the Tacoma Narrows, in
Puget Sound sea urchins, and sand dollars. Dungeness crabs ("Metacarcinus magister") occur throughout Washington waters, including Puget Sound. Many bivalves occur in Puget Sound, such as Pacific oysters ("Crassostrea gigas") and geoduck clams ("Panopea generosa"). The Olympia oyster ("Ostreola conchaphila"), once common in Puget Sound, was depleted by human activities during the 20th century. There are ongoing efforts to restore Olympia oysters in Puget Sound. There are many seabird species of Puget Sound. Among these are grebes such as the western grebe ("Aechmophorus occidentalis"); loons such as the common loon ("Gavia immer"); auks such as the pigeon guillemot ("Cepphus columba"), rhinoceros auklet