The study documents the timing, prevalence and importance of fires in a 105,000-sq-km area of the Northwest Territories, Canada, bounded by long 104 and 112 degrees, lat 60 degrees to tree line. Lightning caused most of the fires and accounted for almost all of the area burned in a 7-year period. In this part of the subarctic, the fires appear to follow a seasonal pulse that progresses in June and July from the SW toward tree line in the NE, retreating in August. The normality of fire in this part of the northern boreal zone is beyond dispute. There is no conclusive proof that fire regime has changed substantially in recent times from what it was previously. The implication is that endemic animals, such as caribou, are adjusted to recurring fires.