Fairfax County is a county in NorthernVirginia, in the United States. As of 2005, the estimated population of the county is 1,041,200; making it by far the most populous jurisdiction in the Commonwealth of Virginia, and larger than seven states. It is the most populous jurisdiction in the Greater Washington Area and has the highest median household income ($100,318 - first to reach six figures) of any county in the United States, recently surpassing its neighbor, Loudoun County.[1] See more at Wikipedia.org...