This dataset contains modeled hourly streamflow in cubic meters per second at each of about eighteen thousand selected operational and water-quality stream gage locations. It was assembled from publicly available retrospective V2.1 National Water Model outputs (See NWM Retrospective source info). The streamflow variable was extracted from model output files and the data were reshaped to optimize read performance. The stream gage locations were derived from several ongoing USGS project gages for evaluation of streamflow, water quality, and real-time monitoring, however only National Water Model identifiers and NHDPlusV2.1 catchment outlet locations (as contained in the National Water Model output files) are used to identify model results. [...]