This data release contains annual estimates of suspended-sediment concentration and load for the Mississippi River, St. Francisville site and the Atchafalaya River, Melville site from 1980-2015. Annual estimates and flow-normalized estimates were generated using the Weighted Regressions on Time, Season and Discharge (WRTDS) model. Input data for the model included suspended-sediment concentrations publicly available from the U.S. Geological Survey (USGS)'s National Water Information System (U.S. Geological Survey, 2016) and daily-mean streamflow estimates from the Army Corps of Engineers (2016) and USGS. These annual concentrations and loads are used to support trend analyses and provide estimates of sediment availability to the Gulf of Mexico. See companion publication for more details (Mize, S.V., Murphy, J.C., Diehl, T.H., and Demcheck, D.K., 2018, Suspended-sediment concentrations and loads in the lower Mississippi and Atchafalaya Rivers decreased by half between 1980 and 2015, Journal of Hydrology, In review). References" U.S. Army Corp of Engineers, 2016, Water levels of Rivers and Lakes data available on the World Wide Web at RiverGages.com, accessed June 10, 2016, at URL http://rivergages.mvr.usace.army.mil U.S. Geological Survey, 2016, National Water Information System—Web interface, accessed November 8, 2017, at http://dx.doi.org/10.5066/F7P55KJN.