The base of the Pittsburgh Coal bed and its stratigraphically (non-coal) equivalent horizon is used to subdivide Upper Pennsylvanian Series strata into the overlying Monongahela Group and the underlying Conemaugh Group in the Appalachian Basin coal region. This dataset depicts areas in which Pittsburgh coal resources were calculated and was obtained largely from published maps. Because different coal thickness criteria were used to delineate the line denoting known resources in Ohio versus West Virginia, an offset is observed at the State boundaries. This dataset is a polygon coverage of counties limited to the extent of the Pittsburgh coal bed resource areas. The file has been generalized from detailed coverages found elsewhere in Professional Paper 1625-C.