Tantallon, Maryland

The Interagency Training Center (ITC), also known as the Fort Washington Facility, is a National Security Agency (NSA) Central Security Service (CSS) school and training facility for technical surveillance counter-measures (TSCM) located in Fort Washington, Maryland. The U.S. government requires that all TSCM technicians be certified at the ITC. The facility previously housed the Department of Defense's Office of Special Technology, which managed technology development and acquisition programs such as the Technical Support Working Group. The site is administered by the U.S. Navy.

Fort Washington is an unincorporated area and census-designated place in Prince George's County, Maryland, United States. It borders the Potomac River, situated 20 miles south of the downtown Washington, DC. As of the 2020 census it had a population of 24,261. The Fort Washington community is located west of Maryland Route 210, with some additional area to the east of the highway.

Fort Washington, located near the community of Fort Washington, Maryland, was for many decades the only defensive fort protecting Washington, D.C. The original fort, overlooking the Potomac River, was completed in 1809, and was begun as Fort Warburton, but renamed in 1808. During the War of 1812, the fort was destroyed by its own garrison during a British advance. The current historic fort—maintained by the National Park Service—was initially constructed in 1824. It is a stone structure with a good cannon shot down the Potomac River. The fort was extensively remodeled in the 1840s and 1890s. The Fort was turned over to the U.S. Department of the Interior in 1946 after its last military personnel departed.The expansive grounds of the present Fort Washington Park, with its extensive hiking/bicycle paths and river view, are a scenic venue for picnicking, fishing, and outdoor recreation. Historical re-enactments are held periodically at the Fort, and there is a small museum. In 2006, repairs were done to shore up the crumbling outer wall, in preparation for the 200th anniversary. The Fort Washington Light, located below the fort, was established in 1857. The current tower, standing 28 feet tall, was constructed in 1882.

Warburton Manor was the colonial home, patented in 1661, of the Digges Family, descendants of Edward Digges, who was Governor of Virginia from 1652 to 1668. Digges was an intimate friend of George and Martha Washington, who visited the house many times. George Washington spent his forty-third birthday at Warburton Manor. Warburton Manor occupied a strategic site on the Potomac River and today it is the site of Fort Washington, designed by Pierre Charles L'Enfant in 1814.

Harmony Hall, located in Fort Washington, Maryland, is managed by the United States National Park Service as part of the National Capital Parks-East system. It has been a National Park Service site since 1966. Harmony Hall is a 2+1⁄2-story Georgian country house built of red brick during the eighteenth century. It is surrounded by 65 acres (26 ha) of land on Broad Creek, a Potomac River tributary.The house was built circa 1769 by Enoch Magruder. After his death, the estate was given to his daughter, Sarah and her husband, Col. William Lyles. The estate was originally called Battersea, but came to be called Harmony Hall some time after 1792, when it was rented to brothers John and Walter Dulaney Addison and their wives. The name "Harmony Hall" commemorates the two couples' harmonious coexistence. Harmony Hall was sold by the Lyles family in 1850. After passing through other owners, the manor was purchased in about 1892 by Robert Stein, his brother Richard, and brother-in-law Joseph Adler. The three had immigrated from Silesia, and engaged in truck farming nearby. They lost control of the manor house in 1929, selling it to Charles Collins, but continued to farm and operate a general store in the area.The home was extensively restored beginning in 1927 by Charles Wallace Collins (1879–1964), a lawyer, writer, and librarian who made his home in Harmony Hall and devoted himself to its restoration after he retired. Collins bequeathed the house to the National Park Service.Beginning in 1985, Frank Calhoun leased the mansion and lived there, investing more than $1 million into the house and its upkeep. After he fell behind on renovations in his early 60s, the Park Service asked Calhoun to leave in 1999. The property has been empty and in accelerating decline since then. Though the Park Service periodically sends in staff and enlists students to clean up the grounds, Harmony Hall competes with many other historic properties for attention and funding.The home has been listed on the National Register of Historic Places since 1980, at which time its condition was described as "excellent". As of January 2010, Harmony Hall is closed to the public.Harmony Hall is also the name given to a community center building, on adjacent property, owned by the Maryland-National Capital Park and Planning Commission and used as their southern area headquarters office. The center includes a fitness center and hosts concerts, stage plays, art exhibits, arts classes, scout meetings, and other cultural programs. The building was originally an elementary school.

Piscataway Creek is an 18.6-mile-long (29.9 km) tributary of the Potomac River in Prince George's County, Maryland. The creek is a tidal arm of the Potomac for its final 2.5 miles (4.0 km), entering the Potomac at Fort Washington Park. Tinkers Creek is a tributary to Piscataway Creek, converging from the north 4.5 miles (7.2 km) upstream of the mouth of the Piscataway. The United States Geological Survey records two variant names for Piscataway Creek: Pascattawaye Creek and Puscattuway Creeke.The Fort Washington Light was built to provide guidance for mariners entering Piscataway Creek from the Potomac River.

Collingwood was a historic mansion in Fort Hunt, Virginia listed on the Fairfax County Inventory of Historic Sites. The mansion was first built in 1859 on a subdivision of George Washington's former River Farm, and significantly altered and expanded in the early 20th century. In July 2019, it was reported that the mansion would be demolished later that year.

Arcturus is a neighborhood within the unincorporated community of Fort Hunt, Virginia in Fairfax County, Virginia, United States. Arcturus lies south of Alexandria between the George Washington Memorial Parkway and the Potomac River.

Waynewood is a populated place in Fairfax County, Virginia, United States. It is located on the Potomac River and the George Washington Memorial Parkway.

River Farm (25 acres (10 ha)), permanent home to the American Horticultural Society (AHS) headquarters, is a (27 acres (11 ha)) landscape located at 7931 East Boulevard Drive, Alexandria, Virginia. The estate takes its name from a larger plot of land which formed an outlying part of George Washington's Mount Vernon estate.

Around 1622, the Piscataway tribe, which led the Conoy Federation, built a town they soon called Kittamaqundi on Piscataway Creek near the modern day town of Piscataway, Prince George's County, Maryland. When English first visited the town, in 1634, they learned it was named after the relatively new Tayac (Emperor) Kittamaquund, who had assumed power the previous year after killing his brother Wannas.

St. John's Church, St. John's Episcopal Church, or St. John's Episcopal Church, Broad Creek (formerly King George's Parish), is a historic Episcopal church located at 9801 Livingston Road in Fort Washington, Prince George's County, Maryland. It is a rectangular Flemish bond brick structure with a bell hipped roof. The interior features a barrel vaulted ceiling with an intricate support system.