Giles County is a county in the US state of Virginia. In the 2000 census the county had a population of 16,657 inhabitants. It is part of the Blacksburg-Christiansburg-Radford metropolitan area. The county seat is Pearisburg. The county was formed in 1806 from portions of Montgomery, Monroe, Tazewell and Wythe counties. It was named in honor of William Branch Giles, the 24th Governor of Virginia.