In the early 1880s, John Wesley Powell – a North American scientist, geographer, and explorer – made a daring suggestion to define the Western U.S. states through watershed boundaries, rather than Cartesian borders. Having spent decades exploring and documenting the physical and cultural geography of the American West, he came to understand the intricate link between water and human organization. Notably, his respect for, and knowledge of, Indigenous communities and cultures influenced his interpretation of human–environment relationships in a way that was far more nuanced than many of his contemporaries. Powell’s dedication to both hydrogeology and ethnology is present throughout his work, particularly in relation to advocating for a “watershed approach” to governance. As Powell described, a watershed is “that area of land, a bounded hydrologic system, within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community”.