This data release contains supplemental data for the following paper: Nelson, A.R., DuRoss, C.B., Mahan, S.A., Gray, H.J., Engelhart, S.E., Witter, R.C., Hawkes, A.D., Horton, B.P., Kelsey, H.M., and Padgett, J.S., 2021, A maximum rupture model for the central and southern Cascadia subduction zone—assessing ages for coastal evidence of megathrust earthquakes and tsunamis: Quaternary Science Reviews 261, https://doi.org/10.1016/j.quascirev.2021.106922. The data include a compilation of new and previously published radiocarbon ages from the original cores from Bradley Lake of Kelsey et al. (2005; odt format), and tables of new and previously published radiocarbon data for 7 of the 13 tidal wetland sites along the coasts of Oregon and northern California, whose ages we compare with the ages from Bradley Lake (odt format). The data files (odt format) also include code for the OxCal (version 4.4; https://c14.arch.ox.ac.uk/oxcal.html) Bayesian software models used with selected radiocarbon ages to calculate age probability density functions for the lake’s earthquake or tsunami-caused disturbance events, and for the stratigraphic contacts produced by earthquakes and tsunamis at 12 of the 13 tidal wetland sites (odt format). An additional text file (odt format) explains the addition of variance to the errors on laboratory reported radiocarbon ages in the tables analyzed prior to 1998, and those analyzed by the National Ocean Sciences AMS Facility (NOSAMS) at the Woods Hole Oceanographic Institution, Woods Hole, Massachusetts. Data describing the results of our recent unsuccessful attempt to use optical dating methods (OSL and IRSL) on quartz grains from tsunami deposits in Bradley Lake to date the deposits can be found in Mahan et al. (2021; U.S. Geological Survey data release, https://doi.org/10.5066/P9YWIDOW).