Washington, D. C., formally the District of Columbia

Retrocession and the Civil War

See also: District of Columbia retrocession and Washington, D.C., in the American Civil War
In the 1830s, the District's southern territory of Alexandria went into economic decline partly due to neglect by Congress.^[20]The city of Alexandria was a major market in the American slave trade, and pro-slavery residents feared that abolitionists in Congress would end slavery in the District, further depressing the economy. Alexandria's citizens petitioned Virginia to take back the land it had donated to form the District, through a process known as retrocession.^[21]
The Virginia General Assembly voted in February 1846 to accept the return of Alexandria and on July 9, 1846, Congress agreed to return all the territory that had been ceded by Virginia. Therefore, the District's current area consists only of the land originally donated by Maryland.^[20] Confirming the fears of pro-slavery Alexandrians, the Compromise of 1850 outlawed the slave trade in the District, although not slavery itself.^[22]
The outbreak of the American Civil War in 1861 led to expansion of the federal government and notable growth in the District's population, including a large influx of freed slaves.^[23] President Abraham Lincoln signed the Compensated Emancipation Act in 1862, which ended slavery in the District of Columbia and freed about 3,100 enslaved persons, nine months prior to the Emancipation Proclamation.^[24] In 1868, Congress granted the District's African American male residents the right to vote in municipal elections.^[23]

Growth and redevelopment

Crowds surrounding theReflecting Pool during the 1963 March on Washington
By 1870, the District's population had grown 75% from the previous census to nearly 132,000 residents.^[25] Despite the city's growth, Washington still had dirt roads and lacked basic sanitation. Some members of Congress suggested moving the capital further west, but President Ulysses S. Grant refused to consider such a proposal.^[26]
Congress passed the Organic Act of 1871, which repealed the individual charters of the cities of Washington and Georgetown, and created a new territorial government for the whole District of Columbia.^[27] President Grant appointed Alexander Robey Shepherd to the position of governor in 1873. Shepherd authorized large-scale projects that greatly modernized Washington, but ultimately bankrupted the District government. In 1874, Congress replaced the territorial government with an appointed three-member Board of Commissioners.^[28]
The city's first motorized streetcars began service in 1888 and generated growth in areas of the District beyond the City of Washington's original boundaries. Washington's urban plan was expanded throughout the District in the following decades.^[29]Georgetown was formally annexed by the City of Washington in 1895.^[30] However, the city had poor housing conditions and strained public works. Washington was the first city in the nation to undergo urban renewal projects as part of the "City Beautiful movement" in the early 1900s.^[31]
Increased federal spending as a result of the New Deal in the 1930s led to the construction of new government buildings, memorials, and museums in Washington.^[32] World War II further increased government activity, adding to the number of federal employees in the capital;^[33] by 1950, the District's population reached its peak of 802,178 residents.^[25]