Mountain Meadows Massacre Monument - Harrison, Ar. - Roadside Attractions on Waymarking.com

The Mountain Meadows massacre was a series of attacks on the Baker–Fancher emigrant wagon train, at Mountain Meadows in southern Utah. The attacks began on September 7 and culminated on September 11, 1857, resulting in the mass slaughter of the emigrant party by members of the Utah Territorial Militia from the Iron County district, together with some Paiute Native Americans. The militia, officially called the Nauvoo Legion, was composed of southern Utah's Mormon settlers (members of The Church of Jesus Christ of Latter-day Saints, or the LDS Church). Intending to leave no witnesses and thus prevent reprisals, the perpetrators killed all the adults and older children—about 120 men, women, and children in total. Seventeen children, all younger than seven, were spared.

The wagon train, mostly families from Arkansas, was bound for California on a route that passed through the Utah Territory, during a conflict later known as the Utah War. After arriving in Salt Lake City, the Baker–Fancher party made their way south, eventually stopping to rest at Mountain Meadows. While the emigrants were camped at the meadow, nearby militia leaders, including Isaac C. Haight and John D. Lee, joined forces to organize an attack on the wagon train.

Intending to give the appearance of Native American aggression, the militia's plan was to arm some Southern Paiute Native Americans and persuade them to join with a larger party of their own militiamen—disguised as Native Americans—in an attack. During the militia's first assault on the wagon train the emigrants fought back, and a five-day siege ensued. Eventually fear spread among the militia's leaders that some emigrants had caught sight of white men and had likely discovered the identity of their attackers. As a result militia commander William H. Dame ordered his forces to kill the emigrants.

By this time the emigrants were running low on water and provisions, and allowed some approaching members of the militia—who carried a white flag—to enter their camp. The militia members assured the emigrants they were protected and escorted them from the hasty fortification. After walking a distance from the camp, the militiamen, with the help of auxiliary forces hiding nearby, attacked the emigrants and killed all of them that they thought were old enough to be potential witnesses to report the attack.

Following the massacre, the perpetrators hastily buried the victims, leaving the bodies vulnerable to wild animals and the climate. Local families took in the surviving children, and many of the victims' possessions were auctioned off. Investigations, after interruption by the American Civil War, resulted in nine indictments during 1874. Of the men indicted, only John D. Lee was tried in a court of law. After two trials in the Utah Territory, Lee was convicted by a jury, sentenced to death, and executed by a Utah firing squad on March 23, 1877.

Today, historians attribute the massacre to a combination of factors, including war hysteria about possible invasion of Mormon territory and hyperbolic Mormon teachings against outsiders, which were part of the excesses of the Mormon Reformation period. Scholars debate whether senior Mormon leadership, including Brigham Young, directly instigated the massacre or if responsibility lay with the local leaders in southern Utah.