Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center extracted sediment and surface samples along transects at three saltmarsh sites situated on the lower end of the Waccasassa River in north-west Florida in order to increase understanding of the region’s environmental history and the ongoing soil chemical processes. To this end, they obtained 17 (ten long and seven short) sediment cores and seven surface samples from saltmarshes along the margins of the river, during field trips in November 2014 and February 2015. Site names are WC01, WC04, WC05, WC10, WC11, WC12, WC20, WC21, WC22, and WC23. Long cores from each location are given the location name and the suffix “R”, surface samples are noted with a “S”, and short cores are given the location name and the suffix “D”, except for the cores taken at sites WC22 and WC23. At those two sites, the short cores were obtained by extracting two parallel peat auger samples to a depth of 50 cm, named WC22Ra-b, and WC23Ra-b, respectively.