Fort Peck Dam, one of the world’s largest earth-filled dams, and Fort Peck Reservoir are featured in this west-southwest-looking, low-oblique photograph. Fort Peck Dam was completed in 1940 as one in a series of dams built in the 1930s, 1940s, and 1950s along the upper watershed of the Missouri River. Besides providing flood control, hydroelectric power, irrigation water, and recreation facilities, the dam serves to impound water for later use from spring rains and snowmelt that swell the Missouri River. Fort Peck Reservoir is approximately 135 miles (217 kilometers) long and a maximum of 16 miles (26 kilometers) wide. The broad valley of the Milk River (upper right) served as the course of the Missouri River before ice age glaciers changed the river to its present course further south. The Milk River is shown joining the Missouri River that meanders eastward toward North Dakota.