Populations of Stone's sheep (Ovis dalli stonei) with and without access to burned ranges were compared. Forage quality (crude protein and acid detergent fiber [ADF]) was similar on both range types throughout the year. Levels of fecal protein followed the seasonal pattern of forage quality and did not differ between populations. Forage quantity was limited during a severe winter, and sheep using burned range had lower counts of lungworm larvae (Protostrongylus spp.) and higher lamb production. Most burned slopes accumulated too much snow to be used by sheep in winter. Horn growth of yearling rams was greater (P < 0.05) on burned ranges, but total horn length was not different at the age that they were shot by hunters.