This U.S. Geological Survey data release contains datasets that combine past data with future projections of nitrogen sources and nitrogen export to the Chesapeake Bay watershed for the years 1950-2050. To help understand the effect of human and environmental changes over this time period, data for nitrogen sources from wastewater, agricultural fertilizer and manure, and atmospheric deposition are combined with datasets of population and land use. These datasets were used in conjunction with a previously calibrated SPAtially Referenced Regression On Watershed attributes (SPARROW) modeling tool to estimate the mean annual loads of total nitrogen to the Chesapeake Bay and nontidal stream reaches in the watershed at a decadal timestep from 1950-2050. SPARROW model output of incremental and total loads for each reach in the Chesapeake Bay watershed are reported in this data release.