Vegetation of the alpine zone of eight mountain ranges in southwestern Montana was classified using IWINSPAN, DECORAN, and STRATA-algorithms embedded within the U.S. Forest Service Northern Region's ECADS (ecological classification and description system) program. Quantitative estimates of vegetation and soil attributes were sampled from 138 plots. Vegetation composition, structure, productivity, associated soil features, and landscape positions are described for the 23 recognized community types that include wetland, snowbed, cushion plant, turf, and grassland physiognomic types. Field identification of community types is facilitated through the inclusion of a diagnostic indicator species-based dichotomous key. Management related obsenrations are posited for this regional alpine zone and for particular vegetation types.