The U.S. Fish and Wildlife Service, part of the US Department of the Interior, is the premier government agency dedicated to the conservation, protection and enhancement of wildlife and wildlife habitats. The Service also helps ensure a healthy environment for people by protecting such ecosystem services as clean air and water. Among other responsibilities, the FWS manages the National Wildlife Refuge System and the Endangered Species Act.
The mission of the National Wildlife Refuge System is to administer a national network of lands and waters for the conservation, management, and where appropriate, restoration of the fish, wildlife, and plant resources and their habitats within the United States for the benefit of present and future generations of Americans.
There are currently 567 national Wildlife Refuges and 38 wetland management areas under FWS control, managing over 95 million acres of land and 740 million acres of water and submerged land in the the US, the Caribbean, and the Pacific Ocean. The largest is Marianas Trench NWR covering 50 million acres of sea bed.