Lake Ilo National Wildlife Refuge (NWR) is located in the Missouri Slope region of western North Dakota, near the Killdeer Mountains. Established in the mid-1930s for migratory waterfowl, this unique Refuge encompasses slightly more than 4,000 acres and is home to approximately 226 bird species, 36 mammals, 9 reptiles/amphibians, and 11 different fish species.