Elevation contour data and an accompanying report provide an updated interpretation of the elevation of the top of Precambrian bedrock in south-central Wisconsin. The elevation surface was developed from geologic and geophysical data, and provides new detail on the entrenched bedrock valleys that were incised into the north and south ranges of the Baraboo Hills. The GIS data include elevation contours, faults, locations of Precambrian outcrops, locations of wells that intersect the Precambrian surface at depth, and historic drill records.