Virginia in the context of "Virginia State Route 150"

Washington, D.C., officially the District of Columbia and commonly known as simply Washington or D.C., is the capital city and federal district of the United States. The city is separated from Virginia to its southwest by the Potomac River and shares land borders with Maryland to its north and east. It was named after George Washington, a Founding Father and the first president of the United States. The district is named for Columbia, the female personification of the nation.

The U.S. Constitution in 1789 called for the creation of a federal district under exclusive jurisdiction of the U.S. Congress. As such, Washington, D.C., is not part of any state, and is not one itself. The Residence Act, adopted on July 16, 1790, approved the creation of the capital district along the Potomac River, and is considered the city's founding date. In 1800, when the capital was moved from Philadelphia, the 6th Congress started meeting in the then-unfinished Capitol Building, and the second president, John Adams, moved into the newly finished White House. In 1801, the District of Columbia, formerly part of Maryland and Virginia and including the existing settlements of Georgetown and Alexandria, was officially made the federal district; initially, the city was a separate settlement within the larger district. In 1846, Congress reduced the size of the district when it returned the land Virginia had ceded, including the city of Alexandria. In 1871, it made the entire district into a single municipality. There have been several failed efforts to make the district into a state since the 1880s, including a statehood bill that passed the House of Representatives in 2021 but was not adopted by the U.S. Senate.

A borough in some U.S. states is a unit of local government or other administrative division below the level of the state. The term is currently used in six states:

• A type of municipality: Connecticut, New Jersey and Pennsylvania (also formerly Michigan and Minnesota)
• A subdivision of a consolidated city, corresponding to another present or previous political subdivision: New York and Virginia
• In Alaska only, a borough is a county-equivalent.

Maryland (US: /ˈmɛrɪlənd/ MERR-il-ənd) is a state in the Mid-Atlantic and South Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east, as well as with the Atlantic Ocean to its east, and the national capital and federal district of Washington, D.C. to the southwest. With a total area of 12,407 square miles (32,130 km), Maryland is the ninth-smallest state by land area, and its population of 6,177,224 ranks it the 18th-most populous state and the fifth-most densely populated. Maryland's capital city is Annapolis, and the state's most populous city is Baltimore.

Maryland's coastline was first explored by Europeans in the 16th century. Prior to that, it was inhabited by several Native American tribes, mostly the Algonquian peoples. One of the original Thirteen Colonies, the Province of Maryland was founded in 1634 by George Calvert, 1st Baron Baltimore, a Catholic convert who sought to provide a religious haven for Catholics persecuted in England. In 1632, Charles I of England granted Lord Baltimore a colonial charter, naming the colony after his wife, Henrietta Maria. In 1649, the Maryland General Assembly passed an Act Concerning Religion, which enshrined the principle of toleration. Religious strife was common in Maryland's early years, and Catholics remained a minority, albeit in greater numbers than in any other English colony.

Arlington County, or simply Arlington, is a county in the U.S. state of Virginia. The county, which is located in the Washington metropolitan area and the broader Northern Virginia region, is positioned directly across from Washington, D.C., the national capital, on the southwestern bank of the Potomac River. The smallest self-governing county in the United States by area, Arlington County has both suburban and urbanized districts. Its urbanized districts are located in proximity to several Washington Metro stations and lines. Its seat of government is located in the Court House neighborhood, which hosts many of its administrative offices and county courthouse.

Originally part of the Nacotchtank tribe's territory prior to the establishment of the Colony of Virginia in 1606, English colonists began settling in Arlington by the 1670s; the area was eventually designated as part of Fairfax County in 1742. The colonial-era economy was mostly based in tobacco agriculture operated with enslaved labor and indentured servants on large plantations. Following the end of the Revolutionary War, Arlington's planters and yeoman farmers transitioned to other crops. Virginia ceded present-day Arlington to help form the District of Columbia, and from 1801 the area was known as Alexandria County; it was eventually retroceded back to Virginia in 1847 as a result of pressure from Alexandria, which was the county's primary commercial center.

The Potomac River (/pəˈtoʊmək/ ) is in the Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is 405 miles (652 km) long, with a drainage area of 14,700 square miles (38,000 km), and is the fourth-largest river along the East Coast of the United States. More than 6 million people live within its watershed.

The river forms part of the borders between Maryland and Washington, D.C., on the left descending bank, and West Virginia and Virginia on the right descending bank. Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low-water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie in Virginia. All navigable parts of the river were designated as a National Recreation Trail in 2006, and the National Oceanic and Atmospheric Administration (NOAA) designated an 18-square-mile (47 km) portion of the river in Charles County, Maryland, as the Mallows Bay–Potomac River National Marine Sanctuary in 2019.

The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the region encompassing the coastline where the Eastern United States meets the Atlantic Ocean; it has always played a major socioeconomic role in the development of the United States.

The region is generally understood to include the U.S. states that border the Atlantic Ocean: Connecticut, Delaware, Florida, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Rhode Island, South Carolina, and Virginia, as well as some landlocked states (Pennsylvania, Vermont, West Virginia, and the district of Washington, D.C.).

The Chesapeake Bay (/ˈtʃɛsəpiːk/ CHESS-ə-peek) is the largest estuary in the United States. The bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Eastern Shore of Maryland, the Eastern Shore of Virginia, and the state of Delaware. The mouth of the bay at its southern point is located between Cape Henry and Cape Charles. With its northern portion in Maryland and the southern part in Virginia, the Chesapeake Bay is a very important feature for the ecology and economy of those two states, as well as others surrounding within its watershed. More than 150 major rivers and streams flow into the bay's 64,299-square-mile (166,534 km) drainage basin, which covers parts of six states (New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia) and all of Washington, D.C.

The bay is approximately 200 miles (320 km) long from its northern headwaters in the Susquehanna River to its outlet in the Atlantic Ocean. It is 2.8 miles (4.5 km) wide at its narrowest (between Kent County's Plum Point near Newtown in the east and the Harford County western shore near Romney Creek) and 30 miles (48 km) at its widest (just south of the mouth of the Potomac River, which divides Maryland from Virginia). Total shoreline including tributaries is 11,684 miles (18,804 km), circumnavigating a surface area of 4,479 square miles (11,601 km). Average depth is 21 feet (6.4 m), reaching a maximum of 174 feet (53 m). The bay is spanned twice, in Maryland by the Chesapeake Bay Bridge from Sandy Point (near Annapolis) to Kent Island and in Virginia by the Chesapeake Bay Bridge–Tunnel connecting Virginia Beach to Cape Charles.

A high water mark is a point that represents the maximum rise of a body of water over land. Such a mark is often the result of a flood, but high water marks may reflect an all-time high, an annual high (highest level to which water rose that year) or the high point for some other division of time. Knowledge of the high water mark for an area is useful in managing the development of that area, particularly in making preparations for flood surges. High water marks from floods have been measured for planning purposes since at least as far back as the civilizations of ancient Egypt. It is a common practice to create a physical marker indicating one or more of the highest water marks for an area, usually with a line at the level to which the water rose, and a notation of the date on which this high water mark was set. This may be a free-standing flood level sign or other marker, or it may be affixed to a building or other structure that was standing at the time of the flood that set the mark.

A high water mark is not necessarily an actual physical mark, but it is possible for water rising to a high point to leave a lasting physical impression such as floodwater staining. A landscape marking left by the high water mark of ordinary tidal action may be called a strandline and is typically composed of debris left by high tide. The area at the top of a beach where debris is deposited is an example of this phenomenon. Where there are tides, this line is formed by the highest position of the tide, and moves up and down the beach on a fortnightly cycle. The debris is chiefly composed of rotting seaweed, but can also include a large amount of litter, either from ships at sea or from sewage outflows.

In the United States, an independent city is a city that is not in the territory of any county or counties and is considered a primary administrative division of its state. Independent cities are classified by the United States Census Bureau as "county equivalents" and may also have similar governmental powers to a consolidated city-county or a unitary authority. However, in the case of a consolidated city-county, a city and a county were merged into a unified jurisdiction in which the county at least nominally exists to this day, whereas an independent city was legally separated from any county or merged with a county that simultaneously ceased to exist even in name.

Of the 41 independent U.S. cities, 38 are in Virginia, whose state constitution makes them a special case. The three independent cities outside Virginia are Baltimore, Maryland; St. Louis, Missouri; and Carson City, Nevada. Baltimore is the most populous independent city in the United States.

Loudoun County (/ˈlaʊdən/) is in the northern part of the Commonwealth of Virginia in the United States. In 2020, the census returned a population of 420,959, making it Virginia's third-most populous county. The county seat is Leesburg. Loudoun County is part of the Washington–Arlington–Alexandria, DC–VA–MD–WV Metropolitan Statistical Area.

As of 2023, Loudoun County had a median household income of $156,821, the highest of any county or county equivalent in the nation.