The Potomac River is a major river in the Mid-Atlantic region of the United States that flows from the Potomac Highlands in West Virginia to the Chesapeake Bay in Maryland. It is 405 miles (652 km) long, with a drainage area of 14,700 square miles (38,000 km2), and is the fourth-largest river along the East Coast of the United States and the 21st-largest in the United States. Over 5 million people live within its watershed.
Interstate 66 (I-66) is an east–west Interstate Highway in the eastern United States. The highway runs from an interchange with I-81 near Middletown, Virginia, on its western end to an interchange with U.S. Route 29 (US 29) in Washington, D.C., at the eastern terminus. Much of the route parallels US 29 or State Route 55 (SR 55) in Virginia. I-66 has no physical or historical connection to the famous US 66, which was located in a different region of the United States.
Cabin John is a census-designated place and an unincorporated area in Montgomery County, Maryland, United States. Its original southern boundary encompassed a section of the Chesapeake and Ohio Canal (C&O) including locks 8–12, and the northern shore of the Potomac River. It is also the access point to Plummers Island, originally owned by The Washington Biologists’ Field Club and called “the most thoroughly studied island in North America.” Cabin John is the location of the Union Arch Bridge built between 1857 and 1864; at the time of its completion, the bridge embodied the longest single-span masonry arch in the world and remains the longest in the United States.
The Woodrow Wilson Memorial Bridge, also known as the Woodrow Wilson Bridge or the Wilson Bridge, is a bascule bridge that spans the Potomac River between Alexandria, Virginia and Oxon Hill, Maryland in Prince George's County, Maryland. The original bridge was one of only a handful of drawbridges in the Interstate Highway System. It contained the only portion of the Interstate System owned and operated by the federal government until construction was completed and it was turned over to the Virginia and Maryland departments of transportation.
The Capital Beltway is a 64-mile (103 km) auxiliary Interstate Highway in the Washington metropolitan area that surrounds Washington, D.C., the capital of the United States, and its inner suburbs in adjacent Maryland and Virginia. It is the basis of the phrase "inside the Beltway", used when referring to issues dealing with US federal government and politics. The highway is signed as Interstate 495 (I-495) for its entire length, and its southern and eastern half runs concurrently with I-95.
The Governor Harry W. Nice Memorial/Senator Thomas "Mac" Middleton Bridge, also known as the Potomac River Bridge, is a 1.7-mile (2.7 km), two-lane continuous truss bridge that spans the Potomac River between Newburg in Charles County, Maryland and Dahlgren in King George County, Virginia, United States. It is one of eight toll facilities operated by the Maryland Transportation Authority, and is one of two toll bridges over the Potomac River. The other, the privately owned Oldtown Low Water Toll Bridge, connects Maryland and West Virginia, far upstream. The new Nice Bridge opened to traffic in October 2022. The original bridge will likely be demolished; no traffic uses it since the new bridge opened.
The Maryland Transportation Authority (MDTA) is an independent state agency responsible for financing, constructing, operating, and maintaining eight transportation facilities, currently consisting of two toll roads, two tunnels, and four bridges in Maryland. It also provides the Maryland Department of Transportation with financing for other revenue producing transportation projects.
Interstate 270 (I-270) is a 34.7-mile (55.8 km) auxiliary Interstate Highway in the U.S. state of Maryland that travels from I-495 just north of Bethesda in Montgomery County north to I-70 in the city of Frederick in Frederick County. It consists of the 32.6-mile (52.5 km) mainline as well as a 2.1-mile (3.4 km) spur that provides access to and from southbound I-495. I-270 is known as the Washington National Pike, and makes up the easternmost stretch of the Dwight D. Eisenhower Highway. Most of the southern part of the route in Montgomery County passes through suburban areas around Rockville and Gaithersburg that are home to many biotech firms. This portion of I-270 is up to 12 lanes wide and consists of a local–express lane configuration as well as high-occupancy vehicle lanes that are in operation during peak travel times. North of the Gaithersburg area, the road continues through the northern part of Montgomery County, passing Germantown and Clarksburg as a six- to eight-lane highway with an HOV lane in the northbound direction only. North of here, I-270 continues through rural areas into Frederick County and toward the city of Frederick as a four-lane freeway.
Maryland Route 4 is a state highway in the U.S. state of Maryland. The highway runs 64.85 miles (104.37 km) from MD 5 in Leonardtown north to Southern Avenue in Suitland at the District of Columbia boundary, beyond which the highway continues into Washington as Pennsylvania Avenue. MD 4 is a four- to six-lane highway that connects Washington and communities around Interstate 95 (I-95)/I-495 with southern Prince George's County with southwestern Anne Arundel County. The highway is the primary highway for the length of Calvert County, during most of which the route runs concurrently with MD 2. MD 4 also connects Calvert and St. Mary's counties via the Governor Thomas Johnson Bridge across the Patuxent River. The highway connects the Southern Maryland county seats of Leonardtown, Prince Frederick, and Upper Marlboro.
The American Legion Memorial Bridge, also known as the American Legion Bridge and formerly as the Cabin John Bridge, is a bridge carrying Interstate 495 across the Potomac River between Montgomery County, Maryland and Fairfax County, Virginia in the United States. It is an American Water Landmark. Plummers Island is located immediately downstream of the bridge.
The Mount Vernon Trail (MVT) is a 17-mile (27 km) long shared use path that travels along the George Washington Memorial Parkway in Northern Virginia between Rosslyn and George Washington's home at Mount Vernon. The trail connects the easternmost portions of Arlington County, the City of Alexandria, and Fairfax County, and travels mostly on dedicated trail with a small portion on city streets. As part of U.S. Bike Route 1, the Potomac Heritage Trail and the East Coast Greenway, the MVT opened in April 1972 as a gravel path and was subsequently expanded and paved.
The Purple Line is a 16.2-mile (26.1 km) light rail line being built to link several Maryland suburbs of Washington, D.C.: Bethesda, Silver Spring, College Park, and New Carrollton. Slated to open in 2026, the line will also enable riders to move between the Maryland branches of the Red, Green, Yellow, and Orange lines of the Washington Metro without riding into central Washington, and between all three lines of the MARC commuter rail system. The project is administered by the Maryland Transit Administration (MTA), an agency of the Maryland Department of Transportation (MDOT), and not the Washington Metropolitan Area Transit Authority (WMATA), which operates Metro.
Mattawoman Creek is a 30.0-mile-long (48.3 km) coastal-plain tributary to the tidal Potomac River with a mouth at Indian Head, Maryland, 20 miles (32 km) downstream of Washington, D.C. It comprises a 23-mile (37 km) river flowing through Prince George's and Charles counties and a 7-mile (11 km) tidal-freshwater estuary in Charles County. About three-fourths of its 94-square-mile (240 km2) watershed lies in Charles County, with the remainder in Prince George's County immediately to the north.
Interstate 95 (I-95) runs 179 miles (288 km) within the commonwealth of Virginia between its borders with North Carolina and Maryland. I-95 meets the northern terminus of I-85 in Petersburg and is concurrent with I-64 for three miles (4.8 km) in Richmond. Although I-95 was originally planned as a highway through Washington, D.C., it was rerouted along the eastern portion of the Capital Beltway concurrent with I-495. From Petersburg to Richmond, I-95 utilized most of the Richmond–Petersburg Turnpike, a former toll road.
Oxon Creek is a stream on the Potomac River which feeds a cove that straddles the border between Washington, D.C. and Prince George's County, Maryland just north of Interstate 495 at Woodrow Wilson Bridge. Oxon Creek heads at the confluence of Oxon Run and Barnaby Run, sometimes referred to as Winkle Doodle Run. It starts just inside the boundary of D.C. and then runs 1.5 miles (2.4 km) to the south and west into Maryland to empty into the Potomac at Goose Island across from the city of Alexandria, Virginia. Before reaching the Potomac, the creek widens to form Oxon Cove which is partially in Maryland and partially in Washington, D.C.. The creek is almost entirely within Oxon Cove National Park, except for the first few feet in D.C. and a portion of the cove on the southside of the Blue Plains Advanced Wastewater Treatment Plant.
The Washington Outer Beltway was a proposed freeway that would have extended further out than the Capital Beltway and encircled Washington, D.C. through the states of Maryland and Virginia. Most of the route was canceled in the 1980s. Parts of it have been built as the Fairfax County Parkway in Virginia, as well as Interstate 370 and the Intercounty Connector in Maryland.
Maryland Route 254 is a state highway in the U.S. state of Maryland. Known as Cobb Island Road, the state highway runs 1.25 miles (2.01 km) from Cobb Island north to MD 257 near Rock Point. MD 254 connects the mainland to Cobb Island, which was originally established as a summer resort in the early 1920s, at the southern end of Charles County. The state highway was constructed as Maryland Route 533 in the early 1930s. The state highway was rebuilt and renumbered as MD 254 in the 1950s.
Herbert Spencer Barber was an American entomologist.
Marc Alan Korman is an American politician from Maryland. He is a member of the Democratic Party who currently serves in the Maryland House of Delegates, representing District 16 in Montgomery County. Since 2023, he has served as the Majority Leader of the Maryland House of Delegates.
The Douglas Point Nuclear Power Plant was proposed in 1973 for a site on the Potomac River to the south of Washington, D.C. by the Potomac Electric Power Company (PEPCO). The proposed generating facility was to be located in Charles County, Maryland, about 30 miles (48 km) south of Washington, D.C. Two boiling water reactors of about 1150 megawatts were proposed, with projected in-service dates of 1981 and 1982. Two 450-foot (140 m) cooling towers were proposed, and water consumption was projected at 108,000 US gallons per minute (410,000 L/min). The project was set aside in the late 1970s. Opposition centered on the plant's effects on striped bass spawning grounds in the Potomac and consequent damage to the striped bass fishery in the Chesapeake Bay.
