This long narrow lake separates Seattle from East King County. Once a formidable barrier to transportation, the lake is now crossed by two floating bridges which have contributed to the rapid growth of this part of the metropolitan area.
Originally draining through a river at Renton, the lake level was reduced when the Ballard Locks were built, connecting Lake Washington directly to Puget Sound through Lake Union.
In addition to Seattle and Renton, the major cities on the lake are Bellevue, Kirkland, and Bothell on the east side and Mercer Island in the middle.