We assessed the risk of impaired condition of the nearly 3700 5th-level watersheds in the contiguous 48 states containing the national forests and grasslands that make up the U.S. Forest Service's National Forest System (NFS). The assessment was based on readily available, relatively consistent nationwide data sets for a series of indicators representing watershed stressors and resources at risk of watershed impairment. Using a set of weights that express the relative importance of the indicators, a summary measure of relative risk of watershed impairment was computed for each entire watershed, each NFS part of each watershed, and each non-NFS part of each watershed. The summary measure reflects the assumption that indicators are linearly related to risk of watershed impairment. The orderings based on these measures provide a first-cut at a consistent nationwide comparison of watersheds with NFS land. Users of the spreadsheets that contain the detailed results of the assessment may alter the weights according to their own understanding of the relative importance of the indicators, producing their own ratings and rankings. Among other things, we find that the non-NFS parts of the watersheds are consistently under much greater stress than the NFS parts, but that the resources at risk are more evenly spread across the NFS and non-NFS parts of the watersheds; and that risk is unevenly spread across the NFS, with most units in the two eastern regions at higher risk than nearly all units in the western regions. The results of this assessment offer a starting point for deciding about risk mitigation efforts, one that could be supplemented by locally available data on additional indicators and by a comparison of the costs and benefits of mitigation options.