The GPM Ground Validation USGS Stream Flow IFloodS dataset was obtained from USGS during the Iowa Flood Studies (IFloodS) field campaign that extended from March 30, 2013 through June 30, 2013. The main goal of IFloodS was to evaluate how well the GPM satellite rainfall data can be used for flood forecasting. The USGS monitors streamflow using gauges on streams and rivers throughout the U.S. For the IFloodS field campaign, streamflow data from about 200 gauges in the Iowa IFloodS study area were downloaded from the USGS web site as support data for the campaign. The USGS streamflow data were collected in real-time and provide measurements at 15-60 minute intervals. These USGS Stream Flow data are available in XML format.