Congress passed the
District of Columbia Organic Act of 1801, which officially organized the district and placed the entire territory under the
exclusive control of the federal government. The area within the district was organized into two counties, the
County of Washington to the east and north of the Potomac River and the
County of Alexandria to the west and south. After the Act's passage, citizens in the district were no longer considered residents of Maryland or Virginia, and their representation in Congress ended.