LDS History, Sep 14, 1857

-- Sep 14, 1857
[Deseret] Mormon leader Brigham Young tried to prevent U.S. troops from entering the territory of Utah, when President James Buchanan sent them into to impose federal law. The Mormons attacked the federal troops' supply lines, burning Fort Bridger, and setting fire to the plains to deprive the advancing army of forage for its horses. At the same time, he readied a plan to evacuate and destroy Salt Lake City, should the federal troops get through. (1)

[Utah War] The conclusion of discussions at meeting in the Historians Office was to declare martial law. (Hosea Stout diary) (2)

-- Sep 15, 1857
[Deseret] Brigham Young calls out the Nauvoo Legion to fight the U.S. Troops if they enter Utah Territory. (3)

[U.S. Religious History] Brigham Young declared martial law and forbade U.S. troops from entering Utah in order to avoid being replaced by Alfred Cumming, a non-Mormon, as governor of Utah. (4)

[Utah War] Gov. Brigham Young issued a proclamation: "Citizens of Utah - We are invaded by a hostile force" without any investigation by the government. He declared his actions justified by "the great first law of self preservation and put the Territory of Utah under martial law, forbidding the troops to enter Salt Lake Valley. He ordered large numbers of armed militia to Echo Canyon and other points to intercept the soldiers and prevent their access to the Valley. (complete text: CHC 4:273-274). (2)

-- Sep 16, 1857
[Utah War] Capt. Van Vliet wrote his report to Gen. Pleasanton of his mission to SLC. He relayed Mormon belief that the Army's purpose was to continue previous religious persecution and would resist to the death the Army's entrance into SLC. If the Army were too large to resist, the Mormons would burn everthing and flee to the mountains. He wrote of his kind and hospitable treatment and his regret that he could not dissuade the determination to resist the Army. (complete text: Mormon Resistance, 50-55) (2)

-- Sep 18, 1857
[Deseret] Col. Johnston and his troops leave Fort Leavenworth, Kansas and are headed for Utah. (3)

-- Sep 29, 1857
[Utah War] Daniel H. Wells, general of the Territorial militia, the Nauvoo Legion (about 3000 troops), left SLC for Echo Canyon, 65 miles east, where he established headquarters. The militia he commanded employed various measures to block the progress of the army through the canyon.
Gov. Young wrote a Proclamation to the commander of the Utah Expedition explaining that he was the legitimate Governor and forbade the Army's presence in the Territory. (complete text: CHC 4:276) (2)

-- Oct 1, 1857-3
[Utah War] With the approach of the Army imminent, Fort Supply and Fort Bridger, two Mormon outposts twelve miles apart in now southwest Wyoming, the hopeful winter quarters for the Army, were burned by the Mormons. (2)

-- Oct 4, 1857
[Utah War] Gen. Daniel Wells issued instructions to annoy the federal troops in every way possible: stampede their animals, burn their wagon trains, burn the country around them, surprise them at night to interrupt their sleep, block their way, but "Take no life." A Mormon, Major Joseph Taylor, who had a copy of these orders was captured by the Army. (complete text: CHC 4:279-280. Some sources leave off the important P.S. with the command: "Take no life.") (2)

-- Oct 5, 1857
[Deseret] Lot Smith leads the Nauvoo Legion on a guerrilla-style attack on the provision wagons of the U.S. Army. Fifty-two wagons belonging to outfitters Russell, Majors and Waddell are burned. The government never reimburses the outfitters and in 1860 they form the Pony Express to earn a government mail contract to keep them from falling into bankruptcy. (3)

-- Oct 5, 1857-6
[Utah War] Lot Smith, with a small company of men, surprised and burned three trains of government stores. No shots were fired or blood shed. The teamsters were disarmed and dismissed. (2)

-- Oct 12, 1857 & 14
[Utah War] Col. Alexander on the 12th and Gov. Young on the 14th exchanged strong letters stating their positions, both warning the other of great loss of life. (complete text: Mormon Resistance, 74-81). (2)

-- Oct 14, 1857
[Utah War] Due to losses from Mormon raids and a foot of snow which fell this day, Col. Alexander called a council and decided to retrace his path. He received communication that day of the approach of Col. Albert S. Johnston to take command who ordered the troops assemble at Black's Fork. (Atlantic Monthly 3:370) (2)

-- During 1857 October
Mormon raiding parties in Wyoming slowed progress of Johnston's Army. (5)

-- Nov 3, 1857
[Deseret] Col. Albert Sidney Johnston catches up with Col. Alexander and replaces him as commander. Johnston orders the regiment to spend the winter in Fort Bridger and to delay the move to Salt Lake City until next spring. (3)

1 - Legends of America, Old West Timeline,
2 - Hale, Van, Mormon Miscellaneous, Utah War Chronology,
3 - Wikipedia, Utah War,
4 - Cline, Austin, History of American Religion: Timeline,
5 - Hemidakaota, "Church Chronology from 1800-2000,"
Mormon History Timeline /Chronology