In this data release, Cenozoic calcareous nannofossil occurrence charts are provided as Microsoft Excel spreadsheets for 15 cores or outcrops from the Gulf Coastal Plain (Alabama, Mississippi, and Georgia). Samples have been assigned a USGS sample number and are organized by depth below (cores and wells) or height above (outcrops) the land surface. Based on their known stratigraphic position, lithology, and specific calcareous nannofossil species content, each sample, where possible, was assigned to a geologic formation, age, and standard Martini (1971) calcareous nannofossil biostratigraphic zone. Five additional reference files are provided: (1) ___location information for each core or outcrop, (2) a list of calcareous nannofossil species found in the Gulf and Atlantic Coastal Plains, (3) a summary showing in which calcareous nannofossil zones calcareous nannofossil species have been found in the Gulf and Atlantic Coastal Plains, (4) a selected list of relevant scientific publications, and (5) a data dictionary that provides a line-by-line and column-by-column listing of what is found in each Excel spreadsheet. All the calcareous nannofossil species names have been updated to be consistent with current nomenclature. As an aid to understanding how biostratigraphic zone assignments were determined, specific species that were used to determine a calcareous nannofossil zone are highlighted, as are anomalous species occurrences resulting from natural physical or biological processes such as sediment reworking or burrowing.