After President James Buchanan appointed a new governor of the territory, Young declared martial law and re-activated the Nauvoo Legion; beginning the Utah War.

During the conflict, the Utah Territorial Militia committed a series of attacks that resulted in the mass murder of at least 120 members of the Baker–Fancher immigrant wagon train, known as the Mountain Meadows Massacre.

In 1858, the war ended when Young agreed to resign as governor and allow federal troops to enter the Utah Territory in exchange for a pardon granted to Mormon settlers from President Buchanan.

[19] In 1831, five missionaries of the Latter Day Saint movement—Eleazer Miller, Elial Strong, Alpheus Gifford, Enos Curtis, and Daniel Bowen—came from the branch of the church in Columbia, Pennsylvania, to preach in Mendon.

Here he became acquainted with Mary Ann Angell, a convert to the faith from Rhode Island, and the two were married in February 1834 and obtained a marriage certificate on March 31, 1834.

[43] When Joseph Smith arrived in Far West, he appointed Young, along with Thomas Marsh and David Patten, as "presidency pro tem" in Missouri.

He joined the Masons in Nauvoo on April 7, 1842, and participated in an early endowment ritual led by Joseph Smith that May and became part of the Anointed Quorum.

[58] Young traveled east with Wilford Woodruff and George A. Smith from July to October 1843 on a mission to raise funds for the Nauvoo temple and its guesthouse.

Rigdon became the president of a separate church organization based in Pittsburgh, Pennsylvania, and several other potential successors emerged to lead what became other denominations of the movement.

[80] Repeated conflict in Nauvoo led Young to relocate his group of Latter-day Saints to the Salt Lake Valley, which was then part of Mexico.

[83] Two days after their arrival, Young and the Twelve Apostles climbed the peak just north of the city and raised the American flag, calling it the "Ensign of Liberty".

[87] Young's expedition was one of the largest and one of the best organized westward treks, and he made various trips back and forth between the Salt Lake Valley and Winter Quarters to assist other companies in their journeys.

[94] During his time as governor, Young directed the establishment of settlements throughout present-day Utah, Idaho, Arizona, Nevada, California, and parts of southern Colorado and northern Mexico.

Under his direction, the Mormons built roads, bridges, forts, and irrigation projects; established public welfare; organized a militia; issued a "selective extermination" order against male Timpanogos;[95] and after a series of wars, eventually made peace with the Native Americans.

During time as prophet and governor, Young encouraged bishops to establish grade schools for their congregations, which would be supported by volunteer work and tithing payments.

[109] On October 16, 1875, Young deeded buildings and land in Provo, Utah, to a board of trustees for establishing an institution of learning, ostensibly as part of the University of Deseret.

[110] Young said, "I hope to see an Academy established in Provo ... at which the children of the Latter-day Saints can receive a good education unmixed with the pernicious atheistic influences that are found in so many of the higher schools of the country.

[116] During his tenure, Young oversaw construction of the Salt Lake Tabernacle and announced plans to build the St. George (1871), Manti (1875), and Logan (1877) temples.

[136] Throughout his time as prophet, Young went to great lengths to deny the assumption that he was the author of the practice of priesthood denial to black men, asserting instead that the Lord was.

Jedediah M. Grant, one of the key figures of the Reformation and one of Young's counselors, traveled throughout the Territory, preaching to Latter-day Saint communities and settlements with the goal of inspiring them to reject sin and turn towards spiritual things.

[150] Leonard J. Arrington reports that Young received a rider at his office on the day of the massacre, and that when he learned of the contemplated attack by members of the church in Parowan and Cedar City, he sent back a letter directing that the Fancher party be allowed to pass through the territory unmolested.

As governor, Young had promised the federal government he would protect migrants passing through Utah Territory, but over 120 men, women, and children were killed in this incident.

The remains of about 40 people were later found and buried, and U.S. Army officer James Henry Carleton had a large cross made from local trees, the transverse beam bearing the engraving, "Vengeance Is Mine, Saith The Lord: I Will Repay" and erected a cairn of rocks at the site.

A large slab of granite was put up on which he had the following words engraved: "Here 120 men, women and children were massacred in cold blood early in September, 1857.

[169] His manuscript history from January 5, 1852, which was published in the Deseret News, reads:The negro … should serve the seed of Abraham; he should not be a ruler, nor vote for men to rule over me nor my brethren.

[170]Young adopted the idea of the Curse of Ham—a racist interpretation of Genesis 9 which white proponents of slavery in antebellum America used to justify enslaving black people of African descent[171]—and applied it liberally and literally.

[3] Of Young's fifty-six wives, twenty-one had never been married before; seventeen were widows; six were divorced; six had living husbands; and the marital status of six others is unknown.

Brigham Young appears at the end of the bande dessinée Le Fil qui chante, the last in the Lucky Luke series by René Goscinny.

[190][191] Arthur Conan Doyle gave Brigham Young a minor but pivotal in-person role in the Sherlock Holmes short novel A Study in Scarlet.

In the 2011 satirical musical The Book of Mormon, Young is portrayed as a tyrannical American regional warlord, cursed by God to have a clitoris for a nose—a parable cautioning against female genital mutilation.