The following are national policies that apply to everyone at a national level.
National Parks: Physical geocaches are not allowed in National Parks or on properties owned or managed by the National Park Service. To list a cache on one of those properties, we would need to be provided with written permission for the cache by the top supervisor/ranger for the area and would also want to pass it by the other reviewers before listing. There is a cache on NPS property in Nebraska because such permission was granted. In the Dakotas, the Mount Rushmore Area is owned and operated by the National Park Service.
National Wildlife Refuges: National Wildlife Refuges have banned physical caches. We cannot list a physical cache in one of those areas. See the information on National Parks above.
National Forests, Wilderness, Recreation, and Grassland Areas: National Forests and Grasslands tend to be open to caching unless told otherwise. In Nebraska and the Dakotas, we know of none off limits. National Wilderness Areas tend to be problematic in many states. We are unaware of any such areas in Nebraska. In the Dakotas, the Black Elk Wilderness is off limits to geocaches. We are unaware of any bans in Nebraska or the Dakotas in National Recreation Areas, although in some other areas some of those have restricted caching.