Data from 391 boreholes (including coreholes) that penetrated buried pre-Cretaceous basement rocks that lie beneath Atlantic Coastal Plain sedimentary deposits in Georgia and South Carolina were compiled from non-proprietary, mostly published sources in order to support subsurface geologic mapping, geologic interpretation of geophysical data (aeromagnetic, gravity, seismic), topical studies as in geochronology, and applications ranging from mineral, energy, and water resources to earthquake hazards in the Charleston seismic zone. Most of the entries are based on previous literature. In a few cases where noted, drill cores or cuttings were examined for basic geologic observations. Boreholes into bedrock beneath the coastal plain near the Fall Line reveal buried extensions of geologic units exposed in the Piedmont, and those closer to the Atlantic coast provide rare insights into deeply buried rock units that have no surface exposures. Data for each borehole include the state, a unique identifier (Well_ID), any alternate identifier(s) (Alt_ID), borehole name or location, year drilled, land surface elevation in feet, top-of-basement depth in feet, total depth of borehole in feet, top-of-basement elevation in feet, basement penetrated by drilling in feet, depth reference (ground level, Kelly bushing, or derrick floor), lithology code, basement type, quality of lithologic data, description of pre-Cretaceous basement rock, sample (drill core or cuttings), latitude and longitude (NAD27), county or city, and reference citations. The data in comma separated values (.csv) format are accompanied by an explanation (.txt), references (.txt), and metadata (.xml). The data file uses standard abbreviations for mineral names where necessary to save space.