This dataset contains modeled hourly streamflow at each about eighteen thousand selected operational and water quality stream gage locations. It was assembled from publicly available retrospective and operational V1.2 National Water Model outputs. 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 projects using gages for evaluation of streamflow, water quality, and real-time monitoring however only National Water Model identifiers and NHDPlus catchment outlet locations are used to identify model results. Relationships between NWIS gages and National Water Model prediction locations were not reviewed for release at the time of publication of this data. Please contact the author for up to date information. All processing resources used for data reformatting and extraction can be found in this repository: https://code.usgs.gov/water/nwm_subset. This supporting code also contains Docker images that are capable of processing real-time National Water Model outputs into similar formats as are in this dataset and providing data services via the THREDDS Data Server. The retrospective is available in one NetCDF file. The operational model run archives are available in .tar.gz archives that contain daily Forecast Model Run Collection files. These data conform as much as possible to the NetCDF-CF Discrete Sampling Geometry conventions and are designed to be aggregated along the reference-time dimension allowing creation of a complete collection of forecast model runs with the THREDDS data server. The retrospective data are available from public cloud data outlets (Such as: https://registry.opendata.aws/nwm-archive/) and the operational outputs were retrieved from an archive maintained at the NOAA National Water Center in Tuscaloosa, AL. Note that some data were missing from this archive, on 5-8-2018 for all operational outputs and 7-17-2017 for long range outputs. The operational model runs include analysis and assimilation, short range, medium range, and an ensemble of four long range model runs. More information on these data are available from the National Water Model v1.2 release notes here. http://www.nws.noaa.gov/os/notification/scn18-16national_water_model.htm. The contents of that html page have been archived with this dataset. The retrospective model run is available from: https://docs.opendata.aws/noaa-nwm-pds/readme.html. The precise data included here should match that exactly but was sourced from NOAA-OWP systems at the National Water Center prior to availability of data from Amazon Public Datasets.