Unison is an unincorporated community village in Loudoun County, Virginia. It is located approximately five miles from Middleburg in the …Unison is an unincorporated community village in Loudoun County, Virginia. It is located approximately five miles from Middleburg in the Loudoun Valley close to the Fauquier County border. Founded in about 1740 by Quakers who had migrated down from Pennsylvania, via Maryland and across the Potomac to the fertile farmlands of Northern Virginia, the village and its surrounds - later to become known as Union, and then Unison - was referred to as "Greenland" or "Butterland" in early 1800s deeds. The name "Butterland" was said to have come about as a nod to the Royal taxes at the time being collected in pounds of butter, rather than coin.