The Bureau of Indian Affairs (BIA), also known as Indian Affairs (IA), is a United States federal agency within the Department of the Interior. It is responsible for implementing federal laws and policies related to Native Americans and Alaska Natives, and administering and managing over 55,700,000 acres (225,000 km2) of reservations held in trust by the U.S. federal government for indigenous tribes. It renders services to roughly 2 million indigenous Americans across 574 federally recognized tribes. The BIA is governed by a director and overseen by the Assistant Secretary for Indian Affairs, who answers to the Secretary of the Interior.

The United States Department of the Interior (DOI) is an executive department of the U.S. federal government responsible for the management and conservation of most federal lands and natural resources. It also administers programs relating to Native Americans, Alaska Natives, Native Hawaiians, territorial affairs, and insular areas of the United States, as well as programs related to historic preservation. About 75% of federal public land is managed by the department, with most of the remainder managed by the Department of Agriculture's Forest Service. The department was created on March 3, 1849. It is headquartered at the Main Interior Building, located at 1849 C Street NW in Washington, D.C.