Hillsboro is a rural town in Loudoun County, Virginia, United States. The population was 114 at the 2020 census. Hillsboro is located in western Loudoun County at 39°11′54″N 77°43′28″W / 39.19833°N 77.72444°W, at the east end of Hillsboro Gap, where the North Fork of Catoctin Creek breaks through Short Hill Mountain, part of the Blue Ridge Mountain…Hillsboro is a rural town in Loudoun County, Virginia, United States. The population was 114 at the 2020 census. Hillsboro is located in western Loudoun County at 39°11′54″N 77°43′28″W / 39.19833°N 77.72444°W, at the east end of Hillsboro Gap, where the North Fork of Catoctin Creek breaks through Short Hill Mountain, part of the Blue Ridge Mountains of Virginia. The town is 4 miles east of the West Virginia border and 11 miles northwest of Leesburg, the Loudoun county seat.