Arlington County is a jurisdiction of 25.8 square miles located across the Potomac River from Washington D.C. The County was originally part of the ten-mile square surveyed in 1791 for the Nation’s Capital. From 1801 to 1847, what are now Arlington and a portion of the City of Alexandria were known as Alexandria County, District of Columbia. In 1847, at the request of the local residents, Congress retroceded Alexandria County to the Commonwealth of Virginia.
In 1870, Alexandria County and the City of Alexandria were formally separated and regular elections were held by a post-Civil War government. Subsequently, in 1920, Alexandria County was renamed Arlington County to eliminate the confusion between these two adjacent jurisdictions. The name “Arlington” was chosen because General Robert E. Lee’s home of that name is located in the County, on the grounds of Arlington National Cemetery.
By law, there are no cities or towns located within the boundaries of the County. In 1922, the Virginia Supreme Court held that Arlington is a continuous, contiguous and homogeneous entity which cannot be subdivided nor can any portion be annexed by neighboring jurisdictions.
The Arlington County government exercises both city and county functions, one of the few urban unitary forms of government in the United States. Arlington’s form of government, the County Manager plan, was implemented in 1932. Arlington was the first county in the United States to choose this form of government. Arlington had an estimated population of 211,700 as of January 1, 2012. The County is almost fully developed; there are no farms and little remaining vacant land.