Three species of rough fescues occur in Canada and the adjacent part of the U.S.A.: Festuca altaica, F. campestris (F. scabrella var. major), and F. halli. Festuca altaica, a wide-ranging species of eastern Asia and northern North America, extends southward in the Canadian Cordillera to about latitude 52° N and is disjunct in eastern Canada (northern Québec, Gaspé Peninsula, western Newfoundland, etc.). Festuca scabrella Torr. in Hook, is a synonym of the earlier published F. altaica Trin. in Ledeb. Rough fescues of southern British Columbia, the southern prairie provinces of Canada, and northwestern U.S.A. that have been called F. scabrella belong to F. campestris and F. hallii, a neglected species. A key to the three taxa and a map of their distribution is presented.