Garrison Dam is an earth-fill embankment dam on the Missouri River in central North Dakota, U.S.
Constructed by the U.S. Army Corps of Engineers from 1947 to 1953, at over two miles (3.2 km) in length, the dam is the fifth-largest earthen dam in the world. The reservoir impounded by the dam is Lake Sakakawea, which extends to Williston and the confluence with the Yellowstone River, near the Montana border. The dam and resulting reservoir inundated approximately one-sixth (16.6%) to one-fourth (25%) of Fort Berthold Indian Reservation's land, resulting in the loss of homes, farmland, and community infrastructure for the Three Affiliated Tribes.
Aerial view from the southeast, impounding Lake Sakakawea on the Missouri River
The Missouri River is a river in the Central and Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Mountains of southwestern Montana, then flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri. The river drains semi-arid watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces. Although a tributary of the Mississippi, the Missouri River is slightly longer and carries a comparable volume of water. When combined with the lower Mississippi River, it forms the world's fourth-longest river system.
The Missouri River in Montana
Holter Lake, a reservoir on the upper Missouri River
The Missouri in North Dakota, which was the furthest upstream that French explorers traveled on the river
The Yellowstone River, the fifth longest tributary of the Missouri, which it joins in North Dakota