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
Department of the East the 1916 Defense Act. It was replaced by the Second Corps Area. The headquarters of the 1853–1861 Department of the East in 1861 was Troy, New York, except for the few years under the command of Gen. Bankhead, when he made his headquarters at Ft. McHenry, in Baltimore, MD. The headquarters of the last Department of the East was originally located in leased office space in New York City until 1878, when the War Department relocated all headquarters functions across the country to army posts due to economic considerations. The headquarters was relocated to Fort Columbus, renamed Fort Jay in