The paper version of the Geologic Map of the eastern part of the Challis National Forest and vicinity, Idaho was compiled by Anna Wilson and Betty Skipp in 1994. The geology was compiled on a 1:250,000 scale topographic base map. TechniGraphic System, Inc. of Fort Collins Colorado digitized this map under contract for N.Shock. G.Green edited and prepared the digital version for publication as a GIS database. The digital geologic map database can be queried in many ways to produce a variety of geologic maps.