This dataset contains digital data that were used for the creation of a geologic map shown in Figure 3 in USGS SIR 2017-5150; Postglacial Eruptive History and Geochemistry of Semisopochnoi Volcano, Western Aleutian Islands, Alaska by Coombs, M.L. and others. The map shows the generalized geology of the island and the locations of stations occupied during field work conducted in the summer of 2005. The data are based on mapping completed during the field work, high-resolution digital imagery, and geochemical and radiometric analyses of rock and soil samples.