The Secretary of the Interior is the top official of the U.S. Department of the Interior. The department itself is responsible for a variety of functions including the preservation and conservation of America’s land and natural resources and the protection of wildlife. In all, the department manages over 507 million acres of land, 476 dams, and 348 reservoirs. Units under the Department of the Interior include the National Park Service (NPS), U.S. Fish and Wildlife Service (USWS), the Bureau of Indian Affairs (BIA) and the U.S. Geological Survey (USGS).