A mediaeval Scottish province, successively a mormaerdom, earldom, a marquisate, and a dukedom of Scotland. Atholl is located around the Tilt river valley in central Scotland, with the Firth of Tay to the southeast and Loch Ness to the northwest. The traditional center of the province was Blair Castle. The present Duke of Atholl maintains the only private army in Europe – the Atholl Highlanders.