Thornhill is a community in the Mid Nithsdale area of Dumfries and also Galloway, Scotland, southern of Sanquhar and also north of Dumfries on the main A76 road. Thornhill sits in the Nithsdale valley with the Carsphairn and also Scaur variety to the west as well as the Lowther hillsides to the eastern. It was initially a little village, planned and also built in 1717 on the Queensberry Estate when traveling connecting Dumfries to Glasgow. The Earl of Queensberry at first named the village 'New Dalgarnock' nevertheless the name did not attain prominent authorization. The town is mostly consisted of a grid pattern with the primary road of Drumlanrig Street (the A76), East and also West Morton Streets, New Street, Townhead Street and Gill Road (the A702). The town is near Drumlanrig Castle, a 17th-century turreted manor once the ancient Douglas stronghold, now house to the Battle each other of Buccleuch and Queensberry. The premises consist of Tibbers Castle which was founded in the 12th or 13th century. One of the most recently published Census data from 2001 puts the population at 1,512 residents.