Formed by the action of retreating glaciers at the end of the last Ice Age, the salt waters of Puget Sound are crucial components of both the ecology and the economy of Western Washington.
The sound begins at the junction of the straits of Juan de Fuca and Georgia. It quickly divides into two major segments, Hood Canal forming the western part and Admiralty Inlet the eastern.
Many islands dot Puget Sound, of which the most important are Whidbey Island (the largest), Bainbridge Island, and Vashon.
The major cities on the shores of Puget Sound are Seattle, Tacoma, and Everett. Washington's capital Olympia is at the extreme southern reach of Puget Sound.