Arlington County, Virginia is 68% larger than Alexandria, Virginia.
Area: 40 km2 calculated
Alexandria is an independent city in the Commonwealth of Virginia. As of the 2010 census, the population was 139,966, in 2013, the population was estimated to be 151,218. Located along the Western bank of the Potomac River, Alexandria is approximately six miles south of downtown Washington, D.C. Wikipedia
Area: 67 km2 calculated
Arlington County is a county in the Commonwealth of Virginia. It is coterminous with the U.S. Census Bureau-designated place of Arlington, which is the second-largest principal city of the Washington, D.C. metropolitan area. Wikipedia