	Introduction

The Department of the Interior (DOI) is a federal executive department responsible for the conservation and use of roughly three-quarters of U.S. public lands. DOI defines its mission as to protect and manage the nation's natural resources and cultural heritage for the benefit of the American people; to provide scientific and scholarly information about those resources and natural hazards; and to exercise the country's trust responsibilities and special commitments to American Indians, Alaska Natives, and island territories under U.S. administration. Initially conceived as a "home department" in 1849 to oversee a broad array of internal affairs, DOI has evolved to become the nation's principal land management agency, charged with administering the use of more than 480 million acres of public lands, 700 million acres of subsurface minerals, and 1.7 billion acres of the outer continental shelf (OCS). Similarly, DOI's executive branch structure and operations are also the subject of administrative scrutiny. As part of DOI's organic legislation, Congress conferred on the Secretary of the Interior the "supervisory and appellate powers" held by the President over the commissioner of Public Buildings, as well as oversight responsibility for both the U.S. Census and the Penitentiary of the District of Columbia. Each of DOI's technical bureaus and programmatic offices has a unique mission and set of responsibilities, as well as a distinct organizational structure that serves to meet its functional duties. The number of employees listed for each bureau reflects the average for the four reporting periods from September 2017 to June 2018, with employment figures rounded to the nearest hundred, as reported to OPM. For the purposes of this report, BIE is not considered a technical bureau of DOI. Bureau of Ocean Energy Management (BOEM)

Established in 2010, the Bureau of Ocean Energy Management (BOEM) manages development of the nation's energy and mineral resources on the outer continental shelf (OCS). As of June 2018, BSEE had approximately 800 employees across the United States. Office of Surface Mining Reclamation and Enforcement (OSMRE)

The Office of Surface Mining Reclamation and Enforcement (OSMRE) was established as a bureau within DOI following passage of the Surface Mining Control and Reclamation Act (SMCRA) in 1977. OSMRE is the smallest of DOI's technical bureaus, employing approximately 400 people nationwide as of June 2018. Fish and Wildlife Service. In response, Congress passed an appropriations bill the following year that authorized the creation of the U.S. Geological Survey (USGS). Departmental Offices and Programs89

In addition to the nine technical bureaus, DOI has multiple departmental offices that provide leadership, coordination, and services to the department's various bureaus and programs. 6. Because OPM data include full-time, part-time, and seasonal staff, employment totals tend to spike during the summer months, when agencies such as NPS, BLM, and FWS increase their seasonal workforce. Table 2 shows DOI employment figures both within and outside the DC core-based statistical area (CBSA). Overview of DOI Appropriations

Discretionary funding for DOI is provided primarily through Title I of the annual Interior, Environment, and Related Agencies appropriations bill. DOI Discretionary Appropriations: FY2018 by Agency

 Figure 4 shows the breakdown of enacted FY2018 appropriations for DOI bureaus, offices, and programs funded through the Interior and the Energy and Water appropriations bills. Supplemental emergency appropriations for FY2018 are shown as a separate segment of the total DOI budget; however, these funds were distributed across several DOI bureaus and programs. Two proposals in particular would affect DOI and its structure. The second recommendation would transfer NOAA's National Marine Fisheries Service from the Department of Commerce to DOI and merge it with the FWS.
The U.S. Department of the Interior (DOI) is a federal executive department responsible for the conservation and administration of the public lands and mineral estate of the United States. DOI describes its mission as protecting and managing the nation's natural resources and cultural heritage for the benefit of the American people; providing scientific and scholarly information about those resources and natural hazards; and exercising the nation's trust responsibilities and special commitments to American Indians, Alaska Natives, and island territories under U.S. administration.
As part of its responsibilities, DOI oversees and fosters the use of more than 480 million acres of public lands, 700 million acres of subsurface minerals, and 1.7 billion acres of the outer continental shelf. Each year, Congress deliberates legislation that could affect DOI's management of this vast federal estate. As a result, understanding the roles and responsibilities of DOI's various components and offices is valuable when crafting legislation that affects the department's operations and ability to fulfill its mission.
DOI primarily implements its responsibilities and mission through nine technical bureaus that make up more than 80% of the agency's workforce. These technical bureaus are the Bureau of Indian Affairs (BIA), Bureau of Land Management (BLM), Bureau of Ocean Energy Management (BOEM), Bureau of Reclamation (Reclamation), Bureau of Safety and Environmental Enforcement (BSEE), National Park Service (NPS), Office of Surface Mining Reclamation and Enforcement (OSMRE), U.S. Fish and Wildlife Service (FWS), and U.S. Geological Survey (USGS). Each of these bureaus has a unique mission and set of responsibilities, as well as a distinct organizational structure that serves to meet its functional duties. In addition to these technical bureaus, DOI has multiple departmental offices, which provide leadership, coordination, and services to DOI's various bureaus and programs.
As of June 2018, DOI employed a staff of 69,563 nationwide across its bureaus and offices. However, total DOI employment figures fluctuate throughout the year, as some bureaus rely on seasonal and part-time staff, increasing staff totals during the summer months. The Office of Personnel Management (OPM) reports the average total DOI employment as 65,350 for the four reporting periods from September 2017 to June 2018. The largest bureau within DOI based on number of staff is NPS, which averaged close to 20,000 staff over the same time period—more than twice the size of the second-largest bureau, BLM. The smallest technical bureau by employment is OSMRE, which averaged just over 400 employees. Approximately 10% of all DOI staff are within the District of Columbia core-based statistical area (CBSA), which includes the District of Columbia and selected counties in Maryland, Virginia, and West Virginia.
Congress provides discretionary appropriations for DOI through two annual appropriations bills: the Interior, Environment, and Related Agencies bill and the Energy and Water appropriations bill. Enacted discretionary appropriations for FY2018 totaled $14.6 billion. DOI also received $566 million in supplemental emergency appropriations in FY2018, for a total of $15.2 billion in discretionary appropriations for FY2018.
The organizational structure of DOI is subject to continual congressional oversight and executive branch examination. In 2017 and 2018, President Trump and then-Secretary of the Interior Ryan Zinke submitted reorganization plans for the department and its bureaus. These plans put forth several recommendations, including the consolidation and transfer of most functions of the Army Corps of Engineers Civil Works Division to DOI, the merger of the Department of Commerce's National Marine Fisheries Service with FWS, and the creation of 12 "Unified Regional Boundaries" across DOI's various bureaus.