ABSTRACTThis article examines the current practice of assessing a project’s cumulative effects to health and well-being in a region characterized by a legacy of resource development and Indigenous land use. The context is hydroelectric development in northern Manitoba, Canada. Based on a review of environmental assessment (EA) regulatory applications and panel reports, results indicate that the consideration of health in EA has improved over time, with proponents adopting a holistic definition of health, but impact analyses remained restricted to physical health conditions with social and cultural health impacts to Indigenous communities receiving only limited attention. Multiple common indicators were identified across recent EA applications that relate to health and well-being, but they were not mapped to health determinants, supported by only limited analysis of causal mechanisms, and rarely used to assess the significance of project actions in combination with past projects and the enduring impacts of a 55-year legacy of hydroelectric development. The article concludes with a discussion of the state of practice and offers suggestions for improved coordination of EA for assessing cumulative effects to health and well-being, including adoption of Indigenous health determinants, and the roles of governments and proponents regarding the consideration of legacy effects in project reviews.