Thornhill is a closed station. It served the country town of Thornhill in Dumfries and Galloway. The station site is a mile or so from the town. Four miles north of Thornhill is Drumlanrig Castle, home to the Duke of Buccleuch and Queensberry. The Glasgow and South Western main line rail route between Kilmarnock and Dumfries is forced to make a long detour to the east of Thornhill and through a long tunnel, rather than the more logical route nearer Thornhill town centre and up the Nith Valley, so as not to be seen from the Buccleuch estate.