Elymus macrourus is a species of grass known by the common names tufted wheatgrass and thickspike wildrye. It is native to northwestern North America in Alaska, Yukon, and the Northwest Territories. It is also present in eastern Siberia. This perennial grass grows in tufts of narrow, erect stems up to about 80 centimeters tall. It grows from a rhizome, resprouting to form new tufts. It also reproduces by seed. This grass easily colonizes disturbed habitat, such as areas recently cleared by fire. It is a useful species for revegetation in appropriate habitat. It helps prevent erosion.