The Cameron Peak Fire and East Troublesome Fire of 2020 were the two largest wildfires in Colorado history. They burned approximately 9% of the Rocky Mountain National Park, raising a concern for trout populations that currently support recreational fishing and success of on-going and future efforts to conserve native trout populations. In this study, we surveyed habitat characteristics and biological communities at 19 sites in summer of 2021 and a subset of 11 sites in summer of 2022 to characterize wildfire impacts on aquatic resources. We were primarily interested in trout population structure and abundance, which were compared to available pre-fire data. In addition, we collected information on physical habitat, water quality, algae and benthic macroinvertebrates because wildfire effects are complex and this array of data helps assist identifying ecological mechanisms that affect aquatic top predators (i.e., trout). The greenback cutthroat trout is listed as state and federally threatened and is the Colorado State Fish. The Colorado River cutthroat trout is a state species of concern and two distinct lineages occur in the burned areas of ROMO. Quantifying wildfire effects on stream ecosystems and trout populations is needed for ROMO to decide whether (1) ongoing conservation actions should continue including the Poudre Headwaters Project, (2) recreational fishing should be regulated, and (3) waters should require trout stocking or will naturally recover via trout immigration from connected populations.For more information see the report here: https://irma.nps.gov/DataStore/Reference/Profile/2304877