The EPA’s National Nutrient Inventory (NNI) assembled nitrogen and phosphorus inputs across the contiguous United States (CONUS) at the county, state, and HUC8 scales, and has recently been augmented to provide comprehensive nutrient input information across CONUS at the HUC12 level annually from 1987 to 2017 with some agricultural variables going back to the 1950s. The NNI contains data on agricultural (crop and livestock), urban, atmospheric, and natural sources of nitrogen and phosphorus. These data are used to derive management relevant metrics, such as agricultural surplus and nutrient use efficiency, which can be used by stakeholders and decisionmakers to optimize nutrient reduction strategies across urban, atmospheric, natural, and agricultural sectors. While useful for understanding broad spatial patterns in landscape nutrient inputs, waterbody or watershed-specific estimates of inputs would additionally facilitate local and national efforts to manage nutrients. StreamCat and LakeCat contain watershed-level characterizations of several hundred natural and anthropogenic landscape features for about 2.6 million stream segments and 376,000 lakes across the CONUS, built on the framework of the National Hydrography Dataset V2 (NHDPlusV2). We developed a process to downscale and incorporate the NNI into StreamCat and LakeCat to produce watershed-level estimates of nutrient inputs. This process refined the resolution of nutrient information from ~92 sq. km at the HUC12 level to ~ 3 sq. km. and will also summarize the NNI for every lake feature in NHDPlusV2 and its watershed. A dasymetric allocation technique was used to translate the NNI data to StreamCat and LakeCat based on the National Land Cover Dataset (NLCD). This dataset represents the highest resolution summarized nutrient input data currently available for the conterminous US, allowing scientists and managers to quickly estimate nutrient inputs at a variety of scales for watersheds and waterbodies of interest leveraging existing data services already built for StreamCat and LakeCat.