Technical Abstract: 'FirstStrike' slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners] was developed by a research team at the USDA-ARS-Forage and Range Research Laboratory and collaborators at the United States Army - Engineer Research and Development Center and was released on 16 October 2006. FirstStrike is a multi-origin composite of four collections from Colorado and Wyoming and has been evaluated extensively on rangeland sites in the western United States with seedling establishment equal to or better than commercially available cultivars. The 20 source plants of FirstStrike originated from four germplasm collections: Ruth 21 - Fort Carson Training Center, CO [53-54 (N/S), 15-16 (E/W)]; Ruth 26 - Fort Carson Training Center, CO [71-72 (N/S), 14-15 (E/W)]; Ruth 31 - 10 mi. north of Rawlings, WY on HWY 287; and Ruth 37 - Gillette, WY near Roadway Inn between Wyoming Highway numbers 14/16 & Railand. Rapid seedling establishment is the key to a successful revegatation planting in the western United States. In seeded trials at Yakama Training Center, Yakima, WA, Camp Guernsey, Guernsey, WY, Fillmore, UT, and Malta, ID when planted at a rate of 1 seed cm-1 pure live seed (PLS), FirstStrike had significantly (P<0.05) more seedlings per unit area (m2) than Pryor in the establishment year. At Fillmore, UT and Malta, ID, initial stand and persistence of FirstStrike were similar to the cultivar San Luis. FirstStrike was similar to or better than Pryor and San Luis for persistence. At Guernsey, WY, dry matter yield was 27% greater (P<0.07) in FirstStrike than Pryor. FirstStrike germinated five days earlier than Pryor on three different soil types (sandy loam, loam, and sandy).