The Great Mississippi Flood of 1927 was the most destructive river flood in the history of the United States, inundating over 27,000 square miles across 10 states and leaving roughly 700,000 people homeless. Triggered by months of unprecedented rainfall across the central U.S. starting in mid-1926, the Mississippi River system finally overwhelmed its flood defenses in the spring of 1927. The disaster resulted in an estimated 250 to 500 deaths, caused roughly $400 million to $1 billion in damages (amounting to one-third of the entire federal budget at the time), and fundamentally reshaped American flood policy, politics, and racial dynamics.