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 faults Lowland. In particular, to the southeast of Mount St. Helens and Mount Rainier they reflect a regional pattern of NNW oriented faulting, including the Entiat Fault in the North Cascades and the Portland Hills and related faults around Portland (see QFFDB fault map). Yet the SHZ and WRZ may be integral to the regional geology of Puget Sound, possibly revealing some deep and significant facets, and may also present significant seismic hazard. The WRZ and SHZ are associated with the "southern Washington Cascades conductor" (SWCC), a formation of enhanced electrical conductivity lying roughly between Riffe Lake and Mounts St. Helens,