Arlington County, Virginia addition to receiving the lowest proportion of Arlington's vote for a Democratic or Republican candidate in the past century. Arlington is part of Virginia's 8th congressional district, represented by Democrat Don Beyer. The United States Postal Service designates zip codes starting with "222" for exclusive use in Arlington County. However, federal institutions, like Ronald Reagan Washington National Airport and The Pentagon use Washington zip codes. Arlington has consistently had the lowest unemployment rate of any jurisdiction in Virginia. The unemployment rate in Arlington was 4.2% in August 2009. 60% of office space in the Rosslyn-Ballston corridor is leased to government
Arlington County, Virginia county having the same name, a movement started to rename Alexandria County. In 1920, the name Arlington County was adopted, after Arlington House, the home of the American Civil War Confederate general Robert E. Lee, which stands on the grounds of what is now Arlington National Cemetery. The Town of Potomac was incorporated as a town in Alexandria County in 1908. The town was annexed by the independent city of Alexandria in 1930. In 1896, an electric trolley line was built from Washington through Ballston, which led to growth in the county (see Northern Virginia trolleys). In 1920, the Virginia