The town of Thornhill is situated 12 miles north of Dumfries.
The underground Auxiliary Unit base, consisted of a bunker with an arched corrugated iron wall and roof, set in the woodlands to the west of the Thornhill golf course car park. It has been backfilled and only the remains of the collapsed tunnel and a single air vent are now visible.
TNA ref WO199/3388,
Hancock data held at B.R.A
Andrew Nicholson, Archaeologist for Dumfries & Galloway Council