The GPM Ground Validation Raw Autonomous Parsivel Unit (APU) IFloodS dataset was collected by 14 Autonomous Parsivel Unit (APU) sites in eastern Iowa during the Global Precipitation Measurement (GPM) mission Iowa Flood Studies (IFloodS) field campaign. The campaign aimed to collect detailed measurements of precipitation at the Earth’s surface using ground instruments and advanced weather radars while simultaneously collecting data from satellites passing overhead. APU is an optical disdrometer system that measures precipitation particle size and fall velocity. This dataset consists of APU-calculated parameters and unfiltered drop spectrum data. The dataset files are available in ASCII text format from April 1 through May 24, 2013. Officially, the IFloodS campaign ran from May 1 to June 15, 2013, but the APUs were installed and had begun collecting data prior to the start of the campaign.