The girl was part of a group of people who were on a boat that got caught in a hydraulic step below a diversion dam about two miles downstream of the Woodside Fishing Access on the Bitterroot River, Ravalli County Sheriff Chris Hoffman said.
Several of the boat's passengers who fell off were reportedly caught in the strong currents behind the dam.
After various failed attempts to resurrect her, the child was transported to St. Patrick Hospital in Missoula where se was pronounced dead.
The child's name has not yet been released.
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