In September 2025, the U.S. Geological Survey, in cooperation with Idaho Power Company, conducted a pilot geophysical survey along the Snake River between the Boise River confluence and Swan Falls Dam in southwestern Idaho. The purpose of the survey was to evaluate the utility of ground-penetrating radar (GPR) for mapping the spatial distribution and thickness of gravel deposits within the river channel. These data support Idaho Power Company’s efforts to design and construct inset floodplains intended to narrow and deepen the channel, reduce solar insolation, and improve downstream thermal conditions for aquatic organisms. The survey included waterborne GPR data collection using 80 MHz and 160 MHz antennas, along with Global Navigation Satellite Systems (GNSS) positioning. Products included in this data release are raw GPR data files, identified channel bed surface (X,Y), interpreted subsurface features (X,Y, and depth below channel bed surface, in meters), tracklines for processed files, and exported radargrams. These datasets provide preliminary information on subsurface conditions and may inform future construction planning along the Snake River.