Arlington County is located in northeast Virginia and is surrounded by Fairfax County and the Falls Church to the southwest, the City of Alexandria to the southeast, and Washington, D.C. to the northeast directly across the Potomac River, which forms the county's northern border. Other landforms also form county borders, particularly Minor's Hill and Upton's Hill on the west.
According to the U.S. Census Bureau, the county has a total area of 26.1 square miles (67.6 km2), of which 26.0 square miles (67.3 km2) is land and 0.1 square miles (0.3 km2) (0.4%) is water. It is the smallest county by...
Source: Wikipedia (as of 04/11/2019). Read more from Wikipedia