The village of Unison in western Loudoun, as if charmed in some way to keep from changing, is a quiet hamlet of well-kept old buildings, with many farmhouses, barns and churches that measure their age in centuries.  They are settled into a landscape of farm fields and stone walls, where the curving hills and stands of trees give way, in their own rhythm, to views of the calm blue line of mountains on the western horizon. 

It’s the roads in Unison that historians get most excited about, says Mitch Diamond of the Unison Preservation Society, which is leading efforts to list this area as a historic district on the state and national registers of historic places.