The National Wildlife Refuge System is a system of protected areas of the United States managed by the United States Fish and Wildlife Service, an agency within the Department of the Interior. The National Wildlife Refuge System is the system of public lands and waters set aside to conserve America's fish, wildlife, and plants.

The mission of the refuge system is: "To administer a national network of lands and waters for the conservation, management, and where appropriate, restoration of fish, wildlife, and plant resources and their habitats within the United States for the benefit of the present and future generations of Americans". The system maintains the biological integrity, diversity, and environmental health of these natural resources and enables for associated public enjoyment of these areas where compatible with conservation efforts.

National Wildlife Refuges manage a range of habitat types, including wetlands, prairies, coastal and marine areas, and temperate, tundra, and boreal forests. The management of each habitat is a complex process of controlling or eradicating invasive species, using fire in a prescribed manner, assuring adequate water resources, and assessing external threats such as development or contamination.

Hundreds of national refuges are home to some 700 species of birds, 220 species of mammals, 250 reptile and amphibian species, and more than 1000 species of fish. Endangered species are a priority of National Wildlife Refuges, with nearly 60 refuges having the primary purpose of conserving in aggregate 280 threatened or endangered species.

The National Wildlife Refuge System welcomes about 65 million visitors each year to participate in outdoor recreational activities. The system manages six wildlife-dependent recreational uses, including hunting, fishing, birding, photography, environmental education, and environmental interpretation. Hunters visit more than 350 hunting programs on refuges and on about 36,000 waterfowl production areas. Opportunities for fresh or saltwater fishing are available at more than 340 refuges. At least one wildlife refuge is in every state.

National Wildlife Refuge System employees are responsible for planning, biological monitoring and habitat conservation, contaminants management, visitor services, outreach and environmental education, heavy equipment operation, law enforcement, and fire management.

The National Wildlife Refuge System deals with urban intrusion/development, habitat fragmentation, degradation of water quantity and quality, climate change, invasive species, increasing demands for recreation, and increasing demands for energy development. The system has provided a habitat for endangered species, migratory birds, plants, and numerous other valuable animals, implemented the NWRS Improvement Act, acquired and protected key critical inholdings, and established leadership in habitat restoration and management.

Under the act, the NWRS has created Comprehensive Conservation Plans (CCPs) for each refuge, developed through consultation with private and public stakeholders. These began a review process by stakeholders beginning in 2013. The CCPs must be consistent with the FWS goals for conservation and wildlife management.^{[full citation needed]}