The Sheldon National Wildlife Refuge is a 573,504-acre (232,089 ha) national wildlife refuge on the northern border of the U.S. state of Nevada. A very small part extends northward into Oregon. It is managed by the United States Fish and Wildlife Service (USFWS) as the Nevada component of the Sheldon-Hart Mountain National Wildlife Refuge Complex, which is headquartered in Lakeview, Oregon. The Sheldon Refuge was noted for its population of wild horses, now all removed.