Fort Marcy (Virginia)

Merrywood is a historic home located in McLean, Virginia on the Palisades overlooking the Potomac River that has hosted several presidents and members of the British royal family. The Georgian Revival style brick dwelling was built in 1919 for Newbold Noyes.

The Marden House is a residence in McLean, Virginia designed by American architect Frank Lloyd Wright. It is located just off Chain Bridge Road and overlooks the Potomac River. Also known as "Fontinalis," it is named after Luis Marden (1913–2003), a writer, photographer, and explorer for National Geographic. It was designed by Wright in 1952 and was completed in 1959 at a cost of $76,000. The spot had caught Marden's eye in 1944 when he and his wife and had been fishing along the Potomac. After purchasing a plot of land, Marden continued the correspondence he had maintained with Wright since 1940, asking the architect to design a home for him. It was not until 1952 that the designs finally came. After Marden moved to a nursing home in 1998, the house was purchased by Jim Kimsey, co-founder of AOL, in 2000 for $2.5 million.

Little Falls Branch, a 3.8-mile-long (6.1 km) tributary stream of the Potomac River, is located in Montgomery County, Maryland. In the 19th century, the stream was also called Powder Mill Branch. It drains portions of Bethesda, Somerset, Friendship Heights, and Washington, D.C., flows under the Chesapeake and Ohio Canal (C&O), and empties into the Potomac at Little Falls rapids, which marks the upper end of the tidal Potomac.

Fort Ethan Allen was an earthwork fortification that the Union Army built in 1861 on the property of Gilbert Vanderwerken in Alexandria County (now Arlington County), Virginia, as part of the Civil War defenses of Washington (see Washington, D.C., in the American Civil War). The remains of the fort are now within Arlington County's Fort Ethan Allen Park.

Pimmit Run is a 7.8-mile-long (12.6 km) stream in northern Virginia that runs from Fairfax County to the Potomac River at Chain Bridge in the Arlingwood neighborhood of Arlington.

The Washington Aqueduct is an aqueduct that provides the public water supply system serving Washington, D.C., and parts of its suburbs, using water from the Potomac River. One of the first major aqueduct projects in the United States, the aqueduct was commissioned by the U.S. Congress in 1852, and construction began in 1853 under the supervision of Montgomery C. Meigs and the U.S. Army Corps of Engineers. Portions of the aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864.: 68 The system is owned and operated by the U.S. Army Corps of Engineers and has been in continuous use ever since. It is listed as a National Historic Landmark and the Union Arch Bridge, where it is listed as a Historic Civil Engineering Landmark.

The Chain Bridge is a viaduct which crosses the Potomac River at Little Falls in Washington, D.C. The steel girder bridge carries close to 22,000 cars a day. It connects Washington with affluent sections of Arlington and Fairfax counties in Virginia. On the Washington side, the bridge connects with Canal Road. Left turns onto the Clara Barton Parkway from the Chain Bridge are prohibited, but the reverse is permitted. On the Virginia side, the bridge connects with State Route 123 (Chain Bridge Road), which provides access to the George Washington Memorial Parkway. The Chain Bridge has three lanes (of which the center is reversible) and can be safely accessed by pedestrians and cyclists. The pedestrian sidewalk provides access to the Chesapeake and Ohio Canal towpath via a ramp. The bridge also carries water mains which provides Arlington County with water from the Washington Aqueduct.

The Dalecarlia Tunnel in Brookmont, Maryland, near Washington, D.C. is a former railroad tunnel that presently carries the Capital Crescent Trail underneath MacArthur Boulevard and the Washington Aqueduct. It was built in 1910 as part of the Georgetown Branch of the Baltimore and Ohio Railroad. It is a Roman arch tunnel, measuring 18 feet (5.5 m) wide by 340 feet (100 m) long. It features decorative brick facings on both ends and is lined with brick throughout its length. CSX Transportation, the successor to the B&O Railroad, ceased train operations through the tunnel in 1985 and officially abandoned the rail line in 1986.

Little Falls Dam, also known as Brookmont Dam, is a low dam on the Potomac River, built in 1959 to divert water for the water supply system of Washington, D.C., just below Mather Gorge, about 2 miles (3.2 km) above Chain Bridge. The 14-foot (4.3 m) dam was constructed by the U.S. Army Corps of Engineers, which is responsible for the D.C. water supply. It contributes roughly 15 to 20 percent of water intake from the Potomac to the Washington Aqueduct, rising to 30 percent in time of drought.The dam blocks fish migration routes several miles below their natural end at the Great Falls of the Potomac River. It has been termed "the drowning machine" in recognition of its danger to boaters and swimmers who can be trapped in the flow at its base. The dam was altered in 2000 to improve fish passage. The profile at the base has also been altered to reduce the chances of swimmer entrapment beneath the surface.

The Intelligence Community Campus-Bethesda (ICC-B) is a campus in Brookmont, Maryland containing offices for several agencies of the United States Intelligence Community. The campus was created in 1945 and initially served as the headquarters of the National Geospatial-Intelligence Agency and its predecessor organizations. In 2012, it was transferred to the Office of the Director of National Intelligence and substantially renovated into an architecturally and functionally modern design.

Sibley Memorial Hospital is a non-profit hospital located in The Palisades neighborhood of Washington, D.C. It is fully accredited by the Joint Commission on Accreditation of Healthcare Organizations, and is licensed by the District of Columbia Department of Health and Human Services. The hospital specializes in surgery, orthopedics, and oncology services. It has been part of Johns Hopkins Medicine since 2010.

Dalecarlia Reservoir is the primary storage basin for drinking water in Washington, D.C., and Arlington County, Virginia. The reservoir is fed by an underground aqueduct in turn fed by low dams which divert portions of the Potomac River near Great Falls and Little Falls. The reservoir is located between Spring Valley and the Palisades, two neighborhoods in Northwest Washington, D.C., and Brookmont, a neighborhood in Montgomery County, Maryland.