Back in the day, the District of Columbia was a square spanning
the Potomac River, with a town called Washington on land donated by
Maryland, and a town called Alexandria on land donated by Virginia.
For a variety of reasons, Alexandria was returned to Virginia in a
process called retrocession that took from 1840 to 1847 to resolve.
During the Civil War, President Lincoln wanted to re-annex
Alexandria for security reasons, but the Senate did not
approve.