We mapped and characterized Quaternary site conditions using shear-wave-velocity (Vs)-profile data for basins along the Wasatch Front urban corridor to provide a basis for estimating soil response during earthquake ground shaking. We map site conditions for each individual basin using surficial geologic mapping as a foundation, taking into account local conditions and subsurface information to delineate units using mean Vs for the upper 30 meters (Vs30) that we relate to International Building Code (IBC) site classes.