The Basin-Scale Opportunity Assessment (BSOA) Initiative, led by the U.S. Department of Energy’s (DOE’s) Water Power Program, established an integrative, three-phase approach for assessing complementary hydropower-environmental opportunities at the scale of a river basin. Phase 1 of this approach is a scoping assessment process for a given river basin that is intended to provide initial identification, classification, screening, and integration of possible hydropower and environmental opportunities for DOE and basin stakeholders to consider carrying forward as appropriate. Phases 2 and 3 involve greater stakeholder engagement and technical analysis pertaining to potential opportunities identified during Phase 1. Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) developed a technical approach and methodology for BSOA Phase 1 assessments and performed assessments for the Bighorn, Connecticut, and Roanoke River basins. This report summarizes the Phase 1 assessment for the Bighorn River basin.