Lewis and Clark expedition data reveals evidence of a narrower and more dynamic Missouri River than the river's current state. Historical observations recorded during their journey suggest that the river was more prone to flooding and exhibited more extensive sandbars and islands. Today, due to human alterations such as dam construction and channelization, the river is deeper, wider, and has reduced flooding frequency. These changes have consequences for riverine ecosystems, habitat connectivity, and water management. Analyzing historical data like the Lewis and Clark journals can deepen our understanding of riverine system dynamics and guide restoration efforts toward more natural ecological function