Today the lake covers 125 square miles, stretching from 25 miles below the Canadian border all the way to the Grand Coulee Dam in the south, making it the largest lake and reservoir in Washington.įor veteran Lake Roosevelt park ranger Beth Lariviere, tooling around the waters of the lake in a Boston Whaler is an everyday way of life. The reservoir the dam created, at times controversial with the large numbers of American Indians in the area, was given the name of the time's most influential president. Dreamed up during the height of the 1930s Depression, the Grand Coulee Dam was built in 1941 as part of a project to irrigate desert areas of the Pacific Northwest, and for the production of electricity. With a surface area of 80,000 acres and a shoreline of 600 miles, boaters can lose themselves for weeks in the pristine beauty of Lake Roosevelt.