Thornhill is a community in the Mid Nithsdale area of Dumfries and also Galloway, Scotland, south of Sanquhar and north of Dumfries on the major A76 road. Thornhill sits in the Nithsdale valley with the Carsphairn as well as Scaur range to the west and the Lowther hills to the eastern. It was originally a little town, planned as well as constructed in 1717 on the Queensberry Estate on the road linking Dumfries to Glasgow. The Earl of Queensberry at first called the town 'New Dalgarnock' nevertheless the name did not accomplish preferred approval. The town is primarily comprised a grid pattern with the primary road of Drumlanrig Street (the A76), East as well as West Morton Streets, New Street, Townhead Street as well as Gill Road (the A702). The community is near Drumlanrig Castle, a 17th-century turreted mansion once the old Douglas garrison, currently residence to the Duke of Buccleuch and Queensberry. The premises include Tibbers Castle which was founded in the 12th or 13th century. The most recently released Census information from 2001 places the population at 1,512 occupants.