Annual loads of selected constituents were estimated for five stations in the Scituate Reservoir drainage area, Rhode Island, for water years 2016 to 2019 as part of a long-term monitoring program in cooperation with the Providence Water Supply Board. This data release includes the water-quality and streamflow data used to estimate annual loads of total phosphorus, dissolved phosphorus, total nitrogen, dissolved nitrogen, and suspended sediment with a custom regression model in the LOADEST program (Runkel and others, 2004) and by direct computation using streamflow and mean constituent concentration. Daily mean values of base flow and event-based stormflow volumes were determined by fixed-base hydrograph separation to partition constituent loads. Quality-control data for water-quality samples collected by the U.S. Geological Survey at 12 stations in the drainage area during water years 2009 to 2019 are also reported. This data release includes 8 tab-delimited text files: StationInfo.txt, QCData.txt, StormEvents.txt, Outliers.txt, CalibrationData_LOADEST.txt, EstimationData_LOADEST.txt, AnnualLoadEstimates.txt, and ModelSummaries.txt. Reference: Runkel, R.L., Crawford, C.G., and Cohn, T.A., 2004, Load estimator (LOADEST)—A FORTRAN program for estimating constituent loads in streams and rivers: U.S. Geological Survey Techniques and Methods, book 4, chap. A5, 69 p., https://doi.org/10.3133/tm4A5.