Volcanic ash is an important component of north Idaho soils and is closely linked to forest productivity. In this study, we selected 84 randomly located sites in the Palouse Range of northern Idaho that were stratified by combinations of solar insolation and elevation. Soil morphological characteristics including presence/absence of a volcanic ash mantle at each of these sites were described. Field data were then combined with primary and secondary terrain attributes derived from DEMs ranging from 5- to 30-m resolution. Decision tree analyses were performed to identify combinations of terrain attributes most strongly associated with the presence or absence of volcanic ash. Results demonstrate that elevation was consistently the single-best predictor of ash presence regardless of DEM resolution. A model of ash presence was constructed using elevation, compound topographic index aspect (CTI), and aspect. The more highly mixed ash mantles were associated with lower elevations, higher CTI values, and more convex plan curvature. Our results suggest that in contrast to the mixed ash mantles, ash deposited at higher elevations remains largely unaffected by erosional and depositional processes. These spatial analyses allow for a more complete understanding of volcanic ash distribution on north Idaho landscapes than can be derived from traditional order 2 and 3 soil surveys.