Recent geologic mapping on the Island of Hawaii is compiled in a detailed new 1:100,000-scale geologic map. The lava flows and pyroclastic deposits of each volcano are assigned to major lithostratigraphic units based on lithology and stratigraphic relations. However, the emphasis of the map is strongly chronostratigraphic. Lavas of latest Pleistocene and Holocene age, which form almost all of the surface area of the Island's three active volcanoes, Kilauea, Mauna Loa, and Hualalai, are divided, on the basis of field relations and radiocarbon ages, into six to eight chronostratigraphic groups. The map constitutes a detailed database for geologic analysis and resource assessment.