BLAIR of Athol, a castle belonging to the duke of Athol, seated in a district of the same name, in Perthshire in Scotland. W. Long. 3. 30. N. Lat. 56. 46. This castle was besieged by the Highland army in 1746; and bravely defended by Sir Andrew Agnew, who was reduced to eat horse's flesh, until he was relieved by the Hesians under the earl of Crawford.