Richmond, Virginia is 2.4 times larger than Arlington County, Virginia.
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
Area: 162 km2 calculated
Richmond is the capital of the Commonwealth of Virginia, in the United States. It is the center of the Richmond Metropolitan Statistical Area and the Greater Richmond Region; since 1871 Richmond has been an independent city. Wikipedia