Not every wagon train heading west was bound for the Pacific Slope. One remarkable group of religious emigrants halted near the Great Salt Lake in what was then Mexican territory. After years of persecution in the East, the Mormons fled west to find religious freedom and communal security.

In the 1820s, an upstate New York farm boy named Joseph Smith Jr. said that he was visited by an angel who led him to golden tablets buried near his home. With the aid of magic stones, he translated the mysterious language on the tablets to produce The Book of Mormon, which he published in 1830. It told the story of an ancient Hebrew civilization in the New World and predicted the appearance of an American prophet who would reestablish Jesus Christ’s undefiled kingdom in America. Converts, attracted to the promise of a pure faith in the midst of antebellum America’s social turmoil and rampant materialism, flocked to the new Church of Jesus Christ of Latter-Day Saints (the Mormons).

Neighbors branded Mormons heretics and drove Smith and his followers from New York to Ohio, then to Missouri, and finally in 1839 to Nauvoo, Illinois, where they built a prosperous community. But after Smith sanctioned “plural marriage” (polygamy), non-Mormons arrested Smith and his brother. On June 27, 1844, a mob stormed the jail and shot both men dead.

The embattled church turned to an extraordinary new leader, Brigham Young, who oversaw a great exodus. In 1846, traveling in 3,700 wagons, 12,000 Mormons made their way to Iowa and then, the following year, to their new home beside the Great Salt Lake. Young described the region as a barren waste, “the paradise of the lizard, the cricket and the rattlesnake.” Within ten years, however, the Mormons developed an irrigation system that made the desert bloom. Under Young’s stern leadership, the Mormons built a thriving community using cooperative labor, not the individualistic and competitive enterprise common among most emigrants.

In 1850, the Mormon kingdom was annexed to the United States as Utah Territory. Shortly afterward, Brigham Young announced that many Mormons practiced polygamy. Although only one Mormon man in five had more than one wife (Young had twenty-three), Young’s statement forced the U.S. government to establish its authority in Utah. In 1857, 2,500 U.S. troops invaded Salt Lake City in what was known as the Mormon War. The bloodless occupation illustrated that most Americans viewed the Mormons as a threat to American morality and institutions.