Arlington County, Virginia area. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from Washington, D.C., of which it was once a part. With a land area of , Arlington is the geographically smallest self-governing county in the U.S., and by reason of state law regarding population density, has no incorporated towns within its borders. Due to the county's proximity to downtown Washington, D.C., Arlington is home to many important installations for the capital region and U.S. government, including the Pentagon, Reagan National Airport, and Arlington National Cemetery. Many schools and universities have campuses in
Fairlington, Arlington, Virginia located in the Fairlington Community Center. All of Fairlington, including the Alexandria portion, is in the 22206 ZIP code area and is served by the United States Postal Service's Shirlington Annex Post Office although the Parkfairfax Post Office in Alexandria is closer to most of Fairlington. Fairlington, Arlington, Virginia Fairlington is an unincorporated neighborhood in Arlington County, Virginia, United States, located adjacent to Shirlington in the southernmost part of the county on the boundary with the City of Alexandria. The main thoroughfares are Interstate 395 (Shirley Highway) which divides the neighborhood into North and South Fairlington, State Route 7 (King