The Provo River Massacre was a violent attack and massacre in 1850 in which 90 Mormon militiamen surrounded an encampment of Timpanogos families on the Provo River, and laid siege for two days. They eventually shot between 40 and 100 Native American men and one woman with guns and a cannon during the siege and subsequent pursuit, capture, and execution of the two groups that fled during the last night. One militiaman died and eighteen were wounded from return fire during the siege.