Grand Coulee Dam – Washington

Grand Coulee Dam is a concrete gravity dam on the Columbia River in the U.S. state of Washington, built to produce hydroelectric power and provide irrigation water.

Constructed between 1933 and 1942, Grand Coulee originally had only two powerhouses. The third powerhouse ("Nat") was completed in 1974 to increase energy production, making it the largest power station in the United States by nameplate capacity at 6,809 MW. The Grand Coulee Dam is the largest man-made dam on the Columbia River in the United States. Congress approved the dam's construction in 1935 and it was completed in 1942.

Power from the dam fueled the growing industries of the Northwest United States during World War II. The dam's reservoir supplies water for the irrigation of 671,000 acres (2,700 km2) downstream.