Holocene-aged corals from reef cores collected throughout the Florida Keys reef tract (FKRT) were dated using a combination of U-series and radiocarbon techniques to quantify the millennial-scale variability in the local radiocarbon reservoir age (ΔR) of the shallow water environments of south Florida. ΔR provides a measure of the deviation of local radiocarbon concentrations of marine environments from the global average and can be used as a tracer of oceanic circulation and local hydrology. U.S. Geological Survey (USGS) scientists combined coral-based estimates of ΔR, using statistical modeling, to reconstruct millennial-scale variability in ΔR at locations on the FKRT with (“nearshore”) and without (“open ocean”) terrestrial influence. USGS scientists also used the models to provide temporally-explicit estimates of ΔR that can be used in radiocarbon calibrations of marine samples from the region. For further information regarding data collection and analysis methods refer to Toth and others (2016, 2017). This research is a part of the USGS Coral Reef Ecosystem Studies Project (http://coastal.er.usgs.gov/crest/).