Arlington County is a county in the Commonwealth of Virginia. It is coterminous with the U.S. Census Bureau-census-designated place of Arlington, which is the second-largest principal city of the Washington metropolitan area. As a result, the county is often referred to in the region simply as "Arlington" or "Arlington, Virginia".
The area that now constitutes Arlington County was originally part of Fairfax County in the Colony of Virginia. Land grants from the British monarch were awarded to prominent Englishmen in exchange for political favors and efforts at development. One of the grantees was Thomas Fairfax, 6th Lord Fairfax of Cameron, who lends his name to both Fairfax County and the City of Fairfax. The name Arlington goes back to Earl Henry Bennet of Arlington, the namesake of a plantation, Arlington Plantation, along the Potomac River, and Arlington House, the family residence on that property. George Washington Parke Custis, grandson of First Lady Martha Washington, acquired this land in 1802. The estate was eventually passed down to Mary Anna Custis Lee, wife of General Robert E. Lee. The property later became Arlington National Cemetery during the American Civil War, and eventually lent its name to present-day Arlington County.