The Mountain Meadows massacre involves a mass slaughter of the Fancher-Baker emigrant wagon train at Mountain Meadows in the Utah Territory by the local Mormon militia in September 1857.
It begins as an attack, quickly turns into a siege, and eventually culminates on September 11, 1857, in the execution of the unarmed emigrants after their surrender.
Local Paiute tribesmen recruited by the militia also participate in both the attack and the massacre.