Established in 1849, the Department of the Interior (DOI) is one of the leading conservation agencies that protects natural and cultural heritage. The department offers various recreational opportunities and conducts several scientific research activities. It conserves and protects fish and wildlife. The Department of the Interior (DOI) employs a staff of more than 65,000 individuals and over 235,000 volunteers. The department maintains approximately 2,400 operating locations across the United States and Puerto Rico. It is responsible for managing a variety of water and underwater resources. The Department of the Interior (DOI) protects nearly 1,922 endangered and threatened species. The department supports Water for America, which conserves and expands existing water supplies.