Lake Washington

 Lake Washington, from a bench in Kirkland, WA

Lake Washington, from a bench in Kirkland, WA

Lake Washington is the largest lake in King County and the second largest natural lake in the state of Washington. Seattle is found on the Western shore of the lake, Bellevue on the eastern, Kenmore on the Northern, and Renton on the south. Mercer Island sits just off of the western shore, in the southern half of the lake, which you'll barely get to see if you take Interstate 90 from Seattle to Bellevue.

The lake is fed by the Sammamish River at its north end and the Cedar River at its south. However, when we talk about "rivers", don't expect the grandeur of the Mississippi or Alleghany. These are smaller rivers, akin to creeks to those of us imagining the Thames or the Danube when we hear the word 'river'.

Lake Washington is a deep, narrow, glacial trough, created by the Vashon glacier as it receded from the area, roughly 12,000 years or so ago. The lake is 20.6 feet above mean lower low tide in Puget Sound, to which it is connected via Lake Union, the Lake Washington ship canal, and the Chittenden Locks. The canal is the only discharge from Lake Washington via the locks and dam at the western end. The development of the canals, dam, and locks resulted in the lowering of the lake 9 feet to its present level

Lake Washington was named by Thomas Mercer in 1854, when he suggested it be named after George Washington, as the new Washington Territory had been named the year before.

Other names for Lake Washington have included the Duwamish/Lushootseed name HAH-choo or Xachu  ,(translating into "great-amount-of-water"), as well as Lake Geneva, Lake Duwamish, and in Chinook (Chinook being the intertribal trading language),  it was called "Hyas Chuck," which means  "Big Lake."

Seattle - How Now Puget Sound


The location of Seattle is unique insofar as it is one of the largest cities in America to be situated upon a sound. It’s not the largest city in America to have this distinction – that’d be New York City, who finds itself on the west end of the Long Island Sound

What defines a sound is dependent upon which geological definition you use; either the Scandinavian definition, which means a strait, or the narrowest part of a straight, or the 18th century English definition, which means a sea inlet that contains islands. This is the definition used for the Puget Sound.

This definition helps explain the fact that Seattle is a coastal city located upon the Pacific Ocean, even if it is around one hundred miles or so from open sea. This is a fact that is easy to ignore at times due to looking across the sound and seeing various aspects of the Olympic Peninsula.

Puget Sound is defined as all waters of the Hood Canal, the Admiralty Inlet, the Possession Sound, and the Saratoga Passage, among others. Essentially, if one were to draw a line from Mount Vernon, to Port Townsend, Puget Sound would include all waters of the inlet from that line, down to Budd Inlet in the south by Olympia.  That’s a body of water that stretches approximately one hundred miles.

Seattle is located on the Eastern Edge of the Puget Sound, and this aspect of the city is the primary, but certainly not only, defining geologic feature of the region.

All of the Puget Sound region was shaped in larger part due to the Fraser Glaciation. Evidence of glaciation is easily seen today all along the Puget Sound area. The Fraser glaciation lasted about 10,000 years and consisted of 3 periods of ice expansion (called “stades”) and 2 ice recessions (called “interstades”). The Puget Sound was shaped by the Puget Lobe portion of the Cordilleran Ice Sheet that was part of the Fraser Glaciation that shaped much of the Montana, Idaho, Washington, British Columbia, the Yukon Territory, and Alaska.  The Puget Lobe portion of this ice sheet made it as far south as modern-day Olympia.  As it retreated over the course of many thousands of years, it geologically shaped many of the water ways of the region, including Puget Sound, as well as Lake Union, Lake Washington, and Lake Sammamish to the east.

The retreat also helps explain the hilly nature of the region, though not so much the mountainous portions, whose shapes were created under different forces.