- Sand Lake NWR is bounded on the east by the Prairie Coteau and on the west by the Missouri Coteau. The refuge lies in the rich, rolling lowlands of the James River valley.
The James River, running 600 miles north and south through the Dakotas, forms a natural flight path for migrating birds. Each spring and fall, thousands of ducks, geese, and other migratory birds stop at Sand Lake.
The area surrounding Sand Lake NWR was once a vast, rolling grassland interrupted only by the slow moving James River. The refuge is comprised of a mosaic of different land types. Primary habitats include marsh and open water, grassland, cropland, and woodlands.
The wetland component of Sand Lake is comprised of two main bodies of water, Sand Lake and Mud Lake. Natural marshes existed prior to the establishment of the refuge, but two major dams on the James, constructed shortly after the refuge was established, serve to enhance the previously existing wetlands.
The refuge supports important habitat for ducks, Canada geese, and many species of marsh and water birds. Fall migrations of snow geese may reach peaks of 250,000 individuals, whereas the spring migration has been documented at over 1.2 million.
It is the home of the world's largest nesting colony of Franklins gulls, and supports other colonial nesting birds including white-faced ibis, Forster's terns, black terns, black-crowned night herons and cattle egrets. This unique area also provides excellent habitat for resident game species, such as white-tailed deer, ring-necked pheasant, and fur bearers.
The refuge is located in the heart of the Prairie Pothole Region.