The 1:100 000 scale bedrock map data of the Geological Survey of Finland (GTK) include material produced during 1948-2007 for the needs of the mapping of mineral resources, for the sustainable exploitation of aggregate resources and for scientific research. These data include lithological information as polygons, bedrock observation points and drilling sites as well as essential tectonic observations, and information on lithological primary structures, ore minerals and metamorphic index minerals. Some 1:100 000 map sheets give both stratigraphical information as well as lithological data. An explanatory text accompanies most map sheets.