page_title: Arlington County, Virginia
section_title: Alexandria County, District of Columbia (D.C.)
hierarchical_section_title: Arlington County, Virginia / History / Alexandria County, District of Columbia (D.C.)
caption_attribution_description: Hopkins map of Alexandria County, Virginia: Includes the present Arlington County and City of Alexandria.
context_page_description: Arlington County is a county in the Commonwealth of Virginia, often referred to simply as Arlington or Arlington, Virginia. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from the District of Columbia, of which it was once a part. The county is coterminous with the U.S. Census Bureau's census-designated place of Arlington. Arlington is considered to be the second-largest "principal city" of the Washington metropolitan area.
  In 2019, the county's population was estimated at 236,842, making Arlington the sixth-largest county in Virginia by population; if it were incorporated as a city, Arlington would be the fourth most-populous city in the state. With a land area of 26 square miles, Arlington is the geographically smallest self-governing county in the U.S., and by reason of state law regarding population density, it has no incorporated towns within its borders. It is the 5th highest-income county in the U.S. by median family income.
  Arlington is home to the Pentagon, Reagan National Airport, and Arlington National Cemetery.
context_section_description: The area that now contains almost all of Arlington County was ceded to the new United States federal government by Virginia, along with most of what is now the city of Alexandria. With the passage of the Residence Act in 1790, Congress approved a new permanent capital to be located on the Potomac River, the exact area to be selected by U.S. President George Washington. The Residence Act originally only allowed the President to select a location within Maryland as far east as what is now the Anacostia River. However, President Washington shifted the federal territory's borders to the southeast in order to include the pre-existing city of Alexandria at the District's southern tip.
  In 1791, Congress, at Washington's request, amended the Residence Act to approve the new site, including the territory ceded by Virginia. However, this amendment to the Residence Act specifically prohibited the "erection of the public buildings otherwise than on the Maryland side of the River Potomac."  As permitted by the United States 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 placed boundary stones at every mile point. Fourteen of these markers were in Virginia and many of the stones are still standing.
  When Congress arrived in the new capital, they passed the Organic Act of 1801 to officially organize 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 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. It included almost all of the present Arlington County, plus part of what is now the independent city of Alexandria. This Act formally established the borders of the area that would eventually become Arlington but the citizens located in the District were no longer considered residents of Maryland or Virginia, thus ending their representation in Congress.
caption: 1878 map of Alexandria County, now (with the removal of Alexandria City) Arlington County
exif: {}