Department of the Interior Headquarters, District of Columbia

The US Department of the Interior is the federal department that manages federal land, water, and native programs. It manages more than 500 million acres of federal land in the USA, about one fifth of the country’s total land mass, about half of which is under the control of the Bureau of Land Management. The department also manages the 410 parks through the National Park Service, and 544 national wildlife refuges managed by the Fish and Wildlife Service. The DOI operates the USGS, the Bureau of Indian Affairs, and the Bureau of Reclamation, which has around 475 dams and 350 reservoirs.