Mount Vernon District

Humphreys National Forest was established in Virginia by the U.S. Forest Service on April 10, 1925 with 3,184 acres (12.89 km2) from part of the Humphreys Military Reservation, now Fort Belvoir. On April 11, 1928 the executive order for its creation was rescinded and the forest was abolished.

Accotink is an unincorporated community in Fairfax County, Virginia, United States. Accotink is located along Accotink Creek within Fort Belvoir.

Accotink Bay Wildlife Refuge is a nature preserve on the grounds of Fort Belvoir in Fairfax County, Virginia, United States. Several other parks, including Mason Neck State Park, Pohick Bay Regional Park, and the Jackson Miles Abbott Wetland Refuge are located nearby. The refuge was established in 1979 to protect sensitive wetlands and wildlife habitats associated with Accotink Bay and to provide opportunities for environmental education and low-intensity recreation. The refuge offers more than eight miles of hiking trails, including a short paved trail for handicapped access. Species native to the preserve include: Foxes Deer American toads Raccoons Black rat snakes Eastern box turtles Various millipedes, including Narceus americanus Various salamanders, including spotted salamanders and red back salamanders Various spiders, including Lycosa aspersaThe Accotink Bay Wildlife Refuge Environmental Education Center is located at the entrance to the refuge. The center features exhibits, videos and trail guides about the refuge and offers nature education programs.A small parking area with space for six cars (two reserved for handicapped) is located just outside the Tulley Gate entrance off Route 1.

The Institute of Heraldry, officially The Institute of Heraldry, Department of the Army, is an activity of the Administrative Assistant to the Secretary of the Army solely responsible for furnishing heraldic services to the President of the United States and all Federal Government agencies. Title 18 of the United States Code, Chapter 33, Section 704 and Title 32 of the Code of Federal Regulations, Part 507 permit the institute to issue directives on how military insignia are displayed, the criteria for issuance, and how insignia will be worn on military uniforms. The activities of The Institute of Heraldry encompass research, design, development, standardization, quality control, and other services relating to official symbolic items—seals, decorations, medals, insignia, badges, flags, and other items awarded to or authorized for official wear or display by federal government personnel and agencies. Limited research and information services concerning official symbolic items are also provided to the general public. The Institute of Heraldry is located at 9325 Gunston Road, Fort Belvoir, Virginia, a military installation in the U.S. Army Military District of Washington. The institute employs 22 Department of the Army civilians.

The Defense Threat Reduction Agency (DTRA) is both a defense agency and a combat support agency within the United States Department of Defense (DoD) for countering weapons of mass destruction (WMD; chemical, biological, radiological, nuclear, and high explosives) and supporting the nuclear enterprise. According to the agency's website its mission states that "DTRA provides cross-cutting solutions to enable the Department of Defense, the United States Government, and international partners to Deter strategic attack against the United States and its allies; Prevent, reduce, and counter WMD and emerging threats; and Prevail against WMD-armed adversaries in crisis and conflict." The agency is headquartered in Fort Belvoir, Virginia.

Fort Belvoir Community Hospital is a Department of Defense medical facility located on Fort Belvoir, Virginia, outside of Washington D.C. In conjunction with Walter Reed National Military Medical Center, Belvoir provides the Military Health System medical capabilities of the National Capital Region Medical Directorate (NCR MD), a joint unit providing comprehensive care to members of the United States Armed Forces located in the capital area, and their families. The facility is located on a U.S. Army installation, but operates as one of the first joint service medical facilities in the U.S. military, staffed with uniformed medical personnel from the Army, Navy, and Air Force. The hospital is one of the largest medical facilities in Northern Virginia, and provides all levels of inpatient and outpatient medical care. The facility maintains a 24 hour emergency department but, like most U.S. military hospitals, transfers patients in need of a trauma center to equipped civilian medical facilities. As part of federal emergency planning in the National Capitol Region, the hospital is also tasked with maintaining unique capabilities to support continuity of government operations in the event of crisis.The $1.03 billion, 1.3 million-square-foot facility opened in August 2011, replacing Fort Belvoir's existing medical facility, DeWitt Army Community Hospital, and integrating significant portions of the former Walter Reed Army Medical Center in Washington, D.C., in accordance with 2005 Base Realignment and Closure Act. In addition to its primary facility at Fort Belvoir, the hospital also operates the DiLorenzo TRICARE Health Clinic (DTHC) at the Pentagon and satellite health centers in Fairfax and Dumfries, Virginia.

Fort Belvoir is a United States Army installation and a census-designated place (CDP) in Fairfax County, Virginia, United States. It was developed on the site of the former Belvoir plantation, seat of the prominent Fairfax family for whom Fairfax County was named. It was known as Camp A. A. Humphreys from 1917 to 1935 and Fort Belvoir afterward. Fort Belvoir is home to a number of significant United States military organizations. With nearly twice as many workers as The Pentagon, Fort Belvoir is the largest employer in Fairfax County. Fort Belvoir comprises three geographically distinct areas: main base, Davison Army Airfield, and Fort Belvoir North.

The Defense Contract Audit Agency (DCAA) is an agency of the United States Department of Defense under the direction of the Under Secretary of Defense (Comptroller). It was established in 1965 to perform all contract audits for the Department of Defense. Previously, the various branches of military service were responsible for their own contract audits. The DCAA's duties include financial and accounting advisory services for the Department of Defense in connection with negotiation, administration and settlement of contracts and subcontracts.

The narrow gauge railway at Camp A. A. Humphreys was a 20 miles (32 km) long 2 ft (610 mm) gauge military railway at what is now Fort Belvoir, Virginia .

The National Museum of the United States Army is the official museum for the history of the United States Army and is just outside Washington, D.C. It opened on November 11, 2020. The objectives of the museum are to honor America's soldiers, preserve Army history, and educate the public about the Army's role in American history. The U.S. Army announced April 16, 2020 that the museum would delay its opening due to the COVID-19 pandemic.The National Museum is located on 84 acres at Fort Belvoir, Virginia, 20 miles south of Washington, D.C. Ground was broken for the museum in September 2016, and it was scheduled to open on June 4, 2020. That opening was delayed as some of the gallery finishing work was suspended in response to COVID-19 which impacted the project timeline. The main building is approximately 185,000 square feet and displays selections from the United States Army Center of Military History. Outside this facility is a park with gardens and a parade ground. Space is included to accommodate ceremonies, reenactments, lectures, educational programs, and reunions.

The Center for Army Analysis (CAA), formerly US Army's Center for Strategy and Force Evaluation, is a US Army organization under the Deputy Chief of Staff G-8 (DCS G-8) which is responsible for analyses that impact the Army at the strategic or institutional level.

Davison Army Airfield or Davison AAF (IATA: DAA, ICAO: KDAA, FAA LID: DAA) is a military use airport serving Fort Belvoir, in Fairfax County, Virginia, United States.The airfield is located 15 miles (24 km) southwest of Washington, D.C. It was named for noted World War II aviation engineer Brig. Gen. Donald Angus Davison.The airfield provided support for Army One from 1957 to 1976 for presidents Dwight Eisenhower, John F. Kennedy, Lyndon Johnson, Richard Nixon, and Gerald Ford. Its role of support for the presidential helicopter ended in 1976 when responsibility for the helicopter was transferred entirely to the United States Marine Corps. The 12th Aviation Battalion (part of The Army Aviation Brigade, TAAB) now operates Davison AAF and the Pentagon helicopter pad. The battalion's 18 UH-60 Blackhawks including 4 VH-60 models ("Gold Tops") is responsible for priority regional transport for US Army and Pentagon senior leadership.The Civil Air Patrol National Capitol Wing uses a small tower for use during exercises and flights, and bases their four Cessna 172 and 182s there.