This map shows isopachs of drift thickness for Alberta at 1:2 000 000 scale. The southern part of the province, from 49 to 56 degrees North, was primarily compiled from existing 1:250 000 bedrock topography maps. The interpretation of the remaining northern portion of the province was based mostly on limited borehole data and information from existing 1:250 000 hydrogeological maps. The exposed areas represent areas where drift is absent or thin and discontinuous. Contour intervals are irregular and depend on local data density.