Alexandria County was part of the original that created the
District of Columbia in 1791 pursuant to Article I, Section 8, paragraph 17, of the
United States Constitution. The portion of the District created from territory ceded by Virginia in
Fairfax County was termed
Alexandria County of the District of Columbia. It included all of the present
Arlington County, Virginia, plus part of what is now the
independent city of
Alexandria, Virginia. The area was
retroceded to Virginia by an act of the
United States Congress on July 9, 1846, following a referendum of its citizens. From 1846 to 1920, the county was known as
Alexandria County, Virginia.