This data release presents a peak-flow frequency analysis (Eash and others, 2013) for U.S. Geological Survey streamgage 05465500 Iowa River at Wapello, Iowa. These methods are used to provide estimates of peak-flow quantiles corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for this streamgage was retrieved from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2022) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (05465500_ffa_2022_WATSTORE.txt), PeakFQ specifications (05465500_ffa_2022.psf), [...]