Upper Souris National Wildlife Refuge in northern North Dakota extends along thirty-five miles of the Souris River valley northwest of Minot. Established in 1935, it protects a river basin important to the northern plains as a refuge and breeding ground for migratory birds and other wildlife. Its 32,092 acres include river-bottom woodlands, floodplains, mixed-grass hills, shrub-covered coulees, and Lake Darling, a 9,600-acre reservoir created by the 1936 Lake Darling Dam to supply downstream marshes. The refuge is especially significant for birdlife, including endangered piping plover habitat and grassland nesting species, and remains an important conservation landscape valued for both scenery and habitat.