This study examines the evolving relationship between the river and the people who lived along its shores, focusing on the period from 1890 to 1950. The analysis proceeds from the assumption that in modern urban, industrial societies, such as the United States, people have increasingly transformed the natural environment into a human artifact. Such is certainly the case with the upper Mississippi. Between the late nineteenth century and the mid-twentieth century, both the river and its valley underwent major alterations that affected both the face of the land and the underlying fabric of the original ecosystems.