Largest lakes & reservoirs in Washington by shoreline length
The length of the exterior shoreline around a lake is measured at the lake’s normal elevation. The shoreline length can be considerably shorter or longer when lake water levels are lower or higher than normal. A lake with many coves has a much longer shoreline than a lake of similar surface area that is nearly circular in shape.When known, the shoreline miles that we report in our statistics include only the lake’s exterior shoreline, and exclude the shorelines of islands located within a lake’s boundaries. In lakes with many islands, those islands’ combined shorelines may exceed a lake’s exterior shoreline.
You can find many of the world’s longest-shoreline lakes on LakeLubbers. Note: For some lakes, "Longest Shorelines" data is unknown or does not apply, so this table may display fewer lakes than the total 58 articles we have published for Washington lakes.
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Below are lakes within USA > US West Region > Washington > Compared by longest shoreline length in miles. This list does not represent all lakes in Washington, only the 58 Washington lake articles we have published on the LakeLubbers website.
Lake name | Shoreline length in miles | Lake description |
---|---|---|
Lake Tapps (Seattle & Puget Sound Region, WA, US West Region, USA, Washington) |
42 mi | Also known as Tapps Reservoir Located in the populous Seattle and Puget Sound Region of Washington, Lake Tapps delivers water supply, recreation and sound fish ecology to residents … |
Mayfield Lake (Seattle & Puget Sound Region, WA, US West Region, USA, Washington) |
34 mi | Mayfield Lake is cradled in the foothills of the Cascades in Lewis County, Washington. This 2,200-acre reservoir is conveniently located close to Moun … |
Whatcom Lake, WA (Northwest Washington & Islands, WA, US West Region, USA, Washington) |
30 mi | Also known as Lake Whatcom Whatcom Lake is a 5,000-acre natural lake surrounded by mountainous terrain located in Whatcom County, Washington. Whatcom is from a Nooksack Indian w … |
Lake Osoyoos, WA / Canada (British Columbia, Canada, Canada, North Central Washington, US West Region, USA, Washington) |
30 mi | Also known as Osoyoos Lake Lake Osoyoos spans more than 5,700 acres and straddles the border of British Columbia, Canada and Washington state in the United States. The Okanagan … |
Alder Lake (Southwest Washington, US West Region, USA, Washington) |
28 mi | Also known as Alder Reservoir Vacationers planning to visit Mount Rainer need to fit beautiful Alder Lake into their plans. This reservoir in the Southwest Region of Washington off … |
Kachess Lake, WA (North Central Washington, US West Region, USA, Washington) |
24 mi | “Kachess” means “more fish,” a name that aptly describes Lake Kachess in North Central region of Washington. The lake is full of fish, and anglers can … |
Duck Lake (Olympic Peninsula & Pacific Coast Region, WA, US West Region, USA, Washington) |
23 mi | Duck Lake is an unlikely candidate for one of the best fishing lakes in southwestern Washington but holds its own with the best of contenders! Located … |
Lake Cushman, WA (Olympic Peninsula & Pacific Coast Region, WA, US West Region, USA, Washington) |
23 mi | Nestled in the foothills of the majestic Olympic Mountains, Lake Cushman is known for its clear, blue water and alpine beauty. With 23 miles of shorel … |
Rock Lake (Northeast Washington, US West Region, USA, Washington) |
19 mi | Deep, dark and mysterious describes Northeast Washington’s Rock Lake. Largest and deepest of the many lakes in the ‘Channeled Scablands’, Rock lake co … |
Lake Sammamish, WA (Seattle & Puget Sound Region, WA, US West Region, USA, Washington) |
18 mi | At just under 5,000 acres, Lake Sammamish is one of the major recreational lakes in the state. The lake provides activities for fishermen, boaters, je … |
Curlew Lake, WA (Northeast Washington, US West Region, USA, Washington) |
16 mi | Nestled in a valley with breathtaking views of Colville National Forest, Ferry National Forest and mountain ranges, Curlew Lake is located 4.8 miles n … |
Lake Wenatchee, WA (North Central Washington, US West Region, USA, Washington) |
13 mi | Lake Wenatchee is a high mountain lake located in the Wenatchee National Forest in the Cascade Mountains of Washington state. Fed by the Little Wenatc … |