The GPM Ground Validation NASA S-Band Dual Polarimetric (NPOL) Doppler Radar IFloodS data set was collected from April 30, 2013 to June 16, 2013 near Traer, Iowa as a part of the Global Precipitation Measurement Mission (GPM) Iowa Flood Studies (IFloodS) campaign. The NASA NPOL radar, developed by a research team from Wallops Flight Facility, is a fully transportable and self-contained S-band (10 cm), scanning dual-polarimetric, Doppler research radar that collected and operated nearly continuously during the IFloodS field campaign. The GPM Ground Validation NASA S-Band Dual Polarimetric (NPOL) Doppler Radar IFloodS data is available in Universal [Radar] Format (UF).