Northern Rocky Mountain landscape patterns are shaped primarily by fire and succession, and conversely, these vegetation patterns influence burning patterns and plant colonization processes. Historical range and variability (HRV) of landscape pattern can be quantified from three sources: (1) historical chronosequences, (2) spatial series, and (3) simulated chronosequences. The last two sources were used to compute HRV for this study. Spatial series were characterized from aerial photographs of 10 similar landscapes on the Bitterroot National Forest, Montana. The LANDSUM model was used to simulate landscape patterns for three landscapes on the Flathead National Forest. Landscape metrics were computed using FRAGSTATS. Results can be used (1) to describe landscape characteristics, (2) to develop baseline threshold values, and (3) to design treatment guidelines for ecosystem management.