What Is The Largest Lake in The State of Washington?

Travel Map IconWASTINGTON - In Washington State, the title of "largest lake" is a tale of two giants: one a sprawling artificial reservoir that stretches toward the Canadian border, and the other a natural, fjord-like wonder that plunges to incredible depths. Both are vital to the Pacific Northwest's identity, offering vastly different experiences for travelers and locals alike.


What Is The Largest Lake in The State of Washington?
What Is The Largest Lake in The State of Washington?

The Man-Made Giant: Franklin D. Roosevelt Lake

By sheer surface area, Franklin D. Roosevelt Lake (commonly known as Lake Roosevelt) is the largest lake in Washington. Created in 1941 by the construction of the Grand Coulee Dam on the Columbia River, it is a massive reservoir that defines the landscape of Northeastern Washington.

  • Surface Area: Approximately 125 square miles (80,000 acres).
  • Shoreline: Over 600 miles.
  • Location: Stretches 150 miles from Grand Coulee Dam to the Canadian border.

Lake Roosevelt is a powerhouse for recreation, managed largely as a National Recreation Area. It's hundreds of miles of shoreline that provide endless opportunities for boat-in camping, houseboating, and sturgeon and walleye fishing. Because it was formed by flooding the Columbia River valley, the lake's geography is characterized by high desert cliffs and pine-forested hills, offering a rugged, expansive feel that is unique to the "Inland Empire" region.



The Natural Wonder: Lake Chelan

If you are looking for the largest natural lake in the state, your destination is Lake Chelan. This narrow, glacially-carved lake is often compared to a Scandinavian fjord due to its steep canyon walls and extreme depth.

  • Surface Area: Approximately 52 square miles (33,000+ acres).
  • Maximum Depth: 1,486 feet (making it the third deepest lake in the U.S.).
  • Location: North-central Washington, stretching into the heart of the North Cascades.

Lake Chelan is famous for its crystal-clear, "ultra-blue" water. While the southern end near the town of Chelan is a sunny haven for vineyards and water sports, the northern end—accessible only by boat or floatplane—leads to the remote village of Stehekin. Here, the lake is flanked by peaks rising 7,000 feet above the water, providing a dramatic gateway into the wilderness of the Cascade Range.




Two very different leaders dominate Washington's aquatic landscape. Franklin D. Roosevelt Lake holds the title for the largest surface area, offering a 150-mile-long playground for boaters and campers in the northeast. On the other hand, Lake Chelan remains the State largest and most famous natural lake, renowned for its incredible 1,486-foot depth and its transition from sun-drenched wine country to the rugged, remote wilderness of the Cascades.