The new basin characteristics include percentages of various land-use types from the 2011 National Land Cover Dataset, percentages of soil types A through D from the SSURGO soils dataset, percent storage from the National Hydrography Dataset, runoff curve number, soil runoff coefficient, and time of concentration. Methods and data used to compute the basin characteristics are indicated on the StreamStats Information Portal, available at https://streamstats.usgs.gov/information-portal/. Limitations for computing some of the basin characteristics and references to the computation methods are provided on the Colorado StreamStats page at https://www.usgs.gov/streamstats/colorado-streamstats. The new basin characteristics were added because they were needed for use in enabling the use of the rational and TR-55 methods for estimating peak-flow frequency statistics for small basins in Colorado. Efforts are underway now to add this functionality to StreamStats for Colorado.