Etched by glaciers over thousands of years, Puget Sound and the branches of the Strait of Juan de Fuca form a trough between the Cascade and Olympic mountain ranges. The last glacier, Vashon, is thought to have receded about 11,000 years ago. The area that is now Seattle was once covered by 3,412 feet of ice. Today, with its cold, deep waters and a shoreline over 2,000 miles long, the Sound provides habitat for 7 types of salmon, 14 species of marine mammals, 31 species of waterfowl, 57 species of birds and over 70 species of terrestrial wildlife.

Although there are variations, the waters of Puget Sound are cold—45ºF to 55ºF; deep—typically 300 feet in the southern Sound and 600 to 800 feet in the northern; and turbulent—twice daily, about 1.46 cubic miles of water pulses in and out of Puget Sound with the strong tides.

Found above the mouth of the Fraser River, the earliest evidence of humans in this area dates their presence to about 8,000 years ago. Archeological evidence indicates the presence of native people south of Tacoma, near the Nisqually River delta, about 5,000 years ago. The British invasion began in 1778 with explorer James Cook, who discovered Cape Flattery while searching for a Northwest Passage. A year later, Captain Charles Barkley sailed into the Strait of Juan de Fuca. In 1825, the Scottish botanist David Douglas collected and described thousands of Northwest plants and trees. His name was given to the mammoth conifer with deeply furrowed bark (the Douglas fir) that is still the standard of the building industry. In 1851, the first settlers arrived on the site of present day Seattle, and three years later the Washington territory was established. In 1889, Washington was named the 42nd state.

The Alaskan gold rush of 1897 to 1899 created a boom economy for Puget Sound cities. In the 1900s, the World Wars made great demands on the lumber, fishing and ship-building industries, which continue to bolster the financial health of the area, along with a thriving aerospace industry, information technology development, and ocean shipping lines. The ports of Seattle and Tacoma are among the busiest container shipping ports in the country. An economic research firm rated the Seattle/Tacoma economy as the strongest in the nation in 2010. In 2015, the Ports of Seattle and Tacoma formed The Northwest Seaport Alliance to manage their respective cargo terminals and jointly report their cargo statistics. The Northwest Seaport Alliances is the 4th largest container port area in the nation. 2018 marked the 150th Anniversary of Washington’s Pilotage Act. It was a time when sailing schooners and sternwheelers were plying the waters and Port Townsend was the pilot station and customs hub for vessels entering Puget Sound. The Puget Sound region continues to be a vital hub of maritime activity in Washington State where one in four jobs links to international trade.