This data release provides the source data and results of a flood frequency analysis for sites in the Mendenhall River Basin, Alaska, that was conducted using USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006). Data are provided for two streamgages that had at least 10 years of annual peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .EMF files), flood frequency parameters, and flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. Flood frequency analysis for the Mendenhall River excluded annual peak-flow data affected by glacial lake outburst floods. These data were intended to support investigations of streamflow in the Mendenhall River Basin.