Construction of the Grand Coulee Dam in Washington began in 1933 and was completed in 1942. It is the largest hydropower producer in the U.S. and also part of the federal Columbia River Power System. Construction of the Grand Coulee Dam in Washington began in 1933 and was completed in 1942. It is the largest hydropower producer in the U.S. and also part of the federal Columbia River Power System.

May 20, 2025