Oreg., Colo., Alta., B.C., N.W.T., Sask., Yukon, Tex., Nebr., Okla., S.Dak., Utah, Alaska, Idaho, Mont., Vt., Wyo., Wash., Ky., Ariz., Calif., Nev., N.Mex.
Agrostis exarata is common and widely distributed in western North America, usually growing in moist ground in open woodlands, river valleys, tidal marshes, and swamp and lake margins; it also grows in dry habitats such as grasslands and shrublands. It extends from Alaska into Mexico, and is also found in Kamchatka and the Kuril Islands. Eastern North American records probably reflect introductions. It readily colonizes roadsides and bare soil, and exhibits ecological and developmental flexibility. Agrostis exarata is recognized here as a single, variable species that includes what others have treated as distinct species or varieties. Cytotaxonomic study might clarify the basis of the observed variation. Agrostis exarata appears to be related to A. densiflora (see below).