Washington, D.C., formally the District of Columbia and commonly referred to as Washington, the District, or simply D.C., is the capital of the United States, founded on July 16, 1790. The City of Washington was originally a separate municipality within the Territory of Columbia until an act of Congress in 1871 effectively merged the City and the Territory into a single entity called the District of Columbia. It is for this reason that the city, while legally named the District of Columbia, is known as Washington, D.C. The city is located on the north bank of the Potomac River and is bordered by the states of Virginia to the southwest and Maryland to the other sides. The District has a resident population of 591,833; however, because of commuters from the surrounding suburbs, its population rises to over one million during the workweek. The Washington Metropolitan Area, of which the District is a part, has a population of 5.3 million, the eighth-largest metropolitan area in the country.
Article One of the United States Constitution provides for a federal district, distinct from the states, to serve as the permanent national capital. The centers of all three branches of the federal government of the United States are located in the District, as are many of the nation's monuments and museums. Washington, D.C., hosts 173 foreign embassies as well as the headquarters of the World Bank, the International Monetary Fund (IMF), the Organization of American States (OAS), the Inter-American Development Bank, and the Pan American Health Organization (PAHO). The headquarters of other institutions such as trade unions, lobbying groups, and professional associations are also located in the District.
The United States Congress has supreme authority over Washington, D.C.; residents of the city therefore have less self-governance than residents of the states. The District has a non-voting at-large Congressional delegate, but no senators. D.C. residents could not vote in presidential elections until the ratification of the Twenty-third Amendment to the Constitution in 1961. If Washington, D.C. were a state, it would rank last in area (behind Rhode Island), second-to-last in population (ahead of Wyoming), first in population density, 35th in gross state product, and first in percentage of African Americans, which would make Washington, D.C., a minority-majority state.
An Algonquian people known as the Nacotchtank inhabited the area around the Anacostia River where Washington now lies when the first Europeans arrived in the 17th century; however, Native American people had largely relocated from the area by the early 18th century. Georgetown was chartered by the Province of Maryland on the north bank of the Potomac River in 1751. The town would be included within the new federal territory established nearly 40 years later. The City of Alexandria, Virginia, founded in 1749, was also originally included within the District.
James Madison expounded the need for a federal district on January 23, 1788, in his "Federalist No. 43", arguing that the national capital needed to be distinct from the states in order to provide for its own maintenance and safety. An attack on the Congress at Philadelphia by a mob of angry soldiers, known as the Pennsylvania Mutiny of 1783, had emphasized the need for the government to see to its own security. Therefore, the authority to establish a federal capital was provided in Article One, Section Eight, of the United States Constitution, which permits a "District (not exceeding ten miles square) as may, by cession of particular states, and the acceptance of Congress, become the seat of the government of the United States". The Constitution does not, however, specify a location for the new capital. In what later became known as the Compromise of 1790, Madison, Alexander Hamilton, and Thomas Jefferson came to an agreement that the federal government would assume war debt carried by the states, on the condition that the new national capital would be located in the South.
On July 16, 1790, the Residence Act provided for a new permanent capital to be located on the Potomac River, the exact area to be selected by President Washington. As permitted by the U.S. Constitution, the initial shape of the federal district was a square, measuring 10 miles (16 km) on each side, totaling 100 square miles (260 km2). During 1791–92, Andrew Ellicott and several assistants, including Benjamin Banneker, surveyed the border of the District with both Maryland and Virginia, placing boundary stones at every mile point; many of the stones are still standing. A new "federal city" was then constructed on the north bank of the Potomac, to the east of the established settlement at Georgetown. On September 9, 1791, the federal city was named in honor of George Washington, and the district was named the Territory of Columbia, Columbia being a poetic name for the United States in use at that time. Congress held its first session in Washington on November 17, 1800.
The Organic Act of 1801 officially organized the District of Columbia and placed the entire federal territory, including the cities of Washington, Georgetown, and Alexandria, under the exclusive control of Congress. Further, the unincorporated territory within the District was organized into two counties: the County of Washington to the east of the Potomac and the County of Alexandria to the west. Following this Act, citizens located in the District were no longer considered residents of Maryland or Virginia, thus ending their representation in Congress.
On August 24–25, 1814, in a raid known as the Burning of Washington, British forces invaded the capital during the War of 1812, in retaliation for the sacking and burning of York (modern-day Toronto). The Capitol, Treasury, and White House were burned and gutted during the attack. Most government buildings were quickly repaired, but the Capitol, which was at the time largely under construction, would not be completed until 1868.
Since 1800, the District's residents have protested their lack of voting representation in Congress. To correct this, various proposals have been offered to return the land ceded to form the District back to Maryland and Virginia. This process is known as retrocession. However, such efforts failed to earn enough support until the 1830s when the District's southern county of Alexandria went into economic decline due to neglect by Congress. Alexandria was also a major market in the American slave trade, and rumors circulated that abolitionists in Congress were attempting to end slavery in the District; such an action would have further depressed Alexandria's economy. Unhappy with Congressional authority over Alexandria, in 1840 the people began to petition for the retrocession of the District's southern territory back to Virginia. The state legislature complied in February 1846, partly because the return of Alexandria provided two additional pro-slavery delegates to the Virginia General Assembly. On July 9, 1846, Congress agreed to return all the District's territory south of the Potomac River back to the Commonwealth of Virginia.
Confirming the fears of pro-slavery Alexandrians, the Compromise of 1850 outlawed the slave trade in the District, though not slavery itself. By 1860, approximately 80% of the city's African American residents were free blacks. The outbreak of the American Civil War in 1861 led to notable growth in the District's population due to the expansion of the federal government and a large influx of freed slaves. In 1862, President Abraham Lincoln signed the Compensated Emancipation Act, which ended slavery in the District of Columbia and freed about 3,100 enslaved persons, nine months prior to the Emancipation Proclamation. By 1870, the District's population had grown to nearly 132,000. Despite the city's growth, Washington still had dirt roads and lacked basic sanitation; the situation was so bad that some members of Congress proposed moving the capital elsewhere.
With the Organic Act of 1871, Congress created a new government for the entire federal territory. This Act effectively combined the City of Washington, Georgetown, and Washington County into a single municipality officially named the District of Columbia. Even though the City of Washington legally ceased to exist after 1871, the name continued in use and the whole city became commonly known as Washington, D.C. In the same Organic Act, Congress also appointed a Board of Public Works charged with modernizing the city. In 1873, President Grant appointed the board's most influential member, Alexander Shepherd, to the new post of governor. That year, Shepherd spent $20 million on public works ($357 million in 2007), which modernized Washington but also bankrupted the city. In 1874, Congress abolished Shepherd's office in favor of direct rule. Additional projects to renovate the city would not be executed until the McMillan Plan in 1901.
The District's population remained relatively stable until the Great Depression in the 1930s when President Franklin D. Roosevelt's New Deal legislation expanded the bureaucracy in Washington. World War II further increased government activity, adding to the number of federal employees in the capital; by 1950, the District's population had reached a peak of 802,178 residents. The Twenty-third Amendment to the United States Constitution was ratified in 1961, granting the District three votes in the Electoral College.
After the assassination of civil rights leader Dr. Martin Luther King Jr., on April 4, 1968, riots broke out in the District, primarily in the U Street, 14th Street, 7th Street, and H Street corridors, centers of black residential and commercial areas. The riots raged for three days until over 13,000 federal and national guard troops managed to quell the violence. Many stores and other buildings were burned; rebuilding was not complete until the late 1990s.
In 1973, Congress enacted the District of Columbia Home Rule Act, providing for an elected mayor and city council for the District. In 1975, Walter Washington became the first elected and first black mayor of the District. However, during the later 1980s and 1990s, city administrations were criticized for mismanagement and waste. In 1995, Congress created the District of Columbia Financial Control Board to oversee all municipal spending and rehabilitate the city government. The District regained control over its finances in September 2001 and the oversight board's operations were suspended.
On September 11, 2001, terrorists hijacked American Airlines Flight 77 and deliberately crashed the plane into the Pentagon in nearby Arlington, Virginia. United Airlines Flight 93, destined for Washington, D.C., crashed in Pennsylvania when passengers tried to recover control of the plane from hijackers.