Lake Washington is a large freshwater ribbon lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest natural lake in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and Kenmore on the north, and surrounds Mercer Island. The lake is fed by the Sammamish River at its north end and the Cedar River at its south.
Lake Washington received its present name in 1854 after Thomas Mercer suggested it be named after George Washington, as the new Washington Territory had been named the year before. Prior names for Lake Washington have included the Duwamish name Xacuabš (Lushootseed: literally great-amount-of-water), as well as Lake Geneva, Lake Duwamish, and the Chinook jargon name, "Hyas Chuck," meaning, "Big Lake."
Open Water Swimming
It is site of several triathlons, endurance races, excursion swims, and open water swimming competitions. It is also site of the Lake Washington Swim that is recognized and sanctioned by the Northwest Open Water Swimming Association.