This report summarizes geomorphic data and analysis from the range front of the San Gabriel Mountains, California, USA. For catchment-average erosion rates, we describe the methodology used to collect samples of detrital sediment, determine concentrations of cosmogenic beryllium-10 in purified quartz isolated from the samples, and use those nuclide concentrations to calculate erosion rates. We also describe the methodology for calculating various topographic metrics from previously published lidar topographic data. These metrics include stream channel concavity, normalized channel steepness index, dimensionless hilltop erosion and dimensionless hilltop relief.