This thesis documents the fire history and assesses the role of fire in the western larch/Douglas-fir forest of the Coram Experimental Forest in northwestern Montana. Primary attention was given to the frequency, areal spread, relative severity, and effects of fires prior to the advent of active suppression efforts in order to determine the natural occurrence and influence of fire. Fire scars and stand age-classes were used to develop a fire chronology for the period 1602 to 1976. The mean fire- free interval during the historical fire period (1735-1910) varied according to topographic location: valley bottom >117 years, montane slopes 121 years, lower subalpine slopes 146 years, and upper subalpine slopes >146 years. A fire occurred somewhere in the 2984 ha experimental forest on an average of once every 11 years during the 374-year record period. The incidence of fire was high in the late 1800's and early 1900's. Most fires were small (20 to 90 ha). However, fragments of charcoal in the soil indicated fire was a widespread occurrence throughout the forest. Evidently most fires were moderately intense with occasional "runs" of high intensity flames which entered the crowns of the overstory, usually near the tops of ridges. Most fires stopped along ridgelines, ravines, and creeks. Single burns thinned the overstory resulting in mixed conifer regeneration and favoring western larch, Douglas-fir, and lodgepole pine. Multiple burns changed the composition usually promoting lodgepole pine. Fire is a major factor creating diversity of forest vegetation on similar sites and has maintained a heterogeneous tree age-class and canopy structure over the landscape.