what region is loudon county in
For the county in Tennessee, see Loudon County, Tennessee. Loudoun County (/ËlaÊdÉn/ LOWD-Én) is a county in the Commonwealth of Virginia. In 2015, the population was estimated at 375,629, making it Virginia's third-most populous county. Loudoun's county seat is Leesburg. Loudoun County is part of the WashingtonâArlingtonâAlexandria, DCâVAâMDâWV Metropolitan Statistical Area.