Big Falls

Big Falls is the largest and lowermost of the Great Falls of the Missouri in western Montana, once dropping 87 feet and spreading up to 900 feet across, making it the broadest and most powerful cataract in the series. Known to the Mandan long before American exploration as part of Minni-Soze-Tanka-Kun-Ya, it was named Grand Falls by William Clark in 1805 during the Lewis and Clark Expedition. Modern engineering has greatly changed it: water diversion to the Ryan Dam hydroelectric plant often reduces the flow to a summer trickle, and the dam has raised the total height to 177 feet. The site still joins natural habitat with deep Indigenous, exploratory, and engineering significance.

Malmstrom AFB, Montana · United States