Our objective was to model 7-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) on small, ungaged streams in the Upper Colorado River Basin. Modeling streamflows is an important tool for understanding landscape-scale drivers of flow and estimating flows where there are no gaged records. We focused our study in the Upper Colorado River Basin, a region that is not only critical for water resources but also projected to experience large future climate shifts toward a drier climate. We used a random forest modeling approach to model the relation between 7-day minimum flow on gaged streams (115 gages) and environmental variables. We then projected 7-day minimum flow to ungaged reaches in the Upper Colorado River Basin using environmental variables for each stream cell in the basin. This data layer shows modeled values for 7-day minimum flow of each stream cell.