This data release contains seasonal application estimates of nitrogen and phosphorus to cropland for watersheds draining to the Puget Sound and the Strait of Juan de Fuca, Washington. The data, which cover the years 2005 through 2020, were used as input to seasonal Spatially Referenced Regression On Watershed attributes (SPARROW) total nitrogen and total phosphorus models that were used to assess nutrient loadings to Puget Sound. The values constitute the seasonal nitrogen and phosphorus application for each incremental catchment represented in the SPARROW models.