The church was officially organized in 1830 by Joseph Smith, Jr., and five followers. Smith, known as "The Prophet," claimed to receive his authority and guidance through divine revelation, and he taught that he was the instrument through which God had restored the church instituted by Jesus Christ. He called others to join him in building the "City of Zion" in preparation for the second coming of Christ. The early years of the church were marked by a series of migrations as hostilities between Mormons and their non-Mormon neighbors caused the Mormons to abandon settlements and move westward. The first temple was built in Kirtland, Ohio, in 1836. In 1841 the group moved to Independence, Missouri, then to northern Missouri, and then across the Mississippi River to what became the Mormon settlement of Nauvoo. In 1844 Joseph Smith was killed by a Gentile mob in Illinois. His death was followed by a brief period of division and dissension within the church over the election of his successor.
Eventually the majority coalesced behind Brigham Young who headed the church until his death in 1877. Under his leadership the Mormons undertook their last forced Migration, arriving in the Salt Lake Valley of Utah in 1847. Young named the region "Deseret" and in 1849 sought recognition from the federal government as a state. Congress refused, and designated a much smaller region as Utah Territory. Troubles with the government, other settlers, and Indians continued, and in 1857, the U.S. Army was sent to the area to confront Young and the Mormons he had gathered together in Salt Lake City. The confrontation was Peaceful, though the federal presence was continued through the establishment of Fort Douglas overlooking Salt Lake City in the 1860s.
From this base the Mormons then spread and settled throughout the intermountain region, primarily through the formation of farming communities and towns. The church hierarchy played a key role in planning and organizing the settlement and development of this region. An important factor in the growth and development of the church and the Mormon settlement of the West was the large influx of migrants assisted by the church's Perpetual Emigrating Fund. Converts were actively sought and encouraged to migrate to Utah. It is estimated that between 1850 and 1900 the church helped some 90,000-100,000 people immigrate to the United States, primarily from England, Denmark, and Switzerland. Today, there are a number of counties within the Mormon region with markedly high Danish and Swissancestry populations.
The Mormons remained fairly isolated in Utah and adjacent areas until the late 1860s when mining, railroads, and manufacturing attracted non-Mormons to the area in ever-increasing numbers, leading once again to conflicts over Social, political, economic, and religious matters. Major issues included the church's role in political affairs, the church's financial holdings and policies, and polygynous marriage by Mormons. This time the U.S. government became actively involved, passing and enforcing legislation aimed at restricting the church's financial practices and Mormon polygyny. By the end of the nineteenth century, the church had made major concessions in its policies as an accommodation to the non-Mormon society within which it had to operate. The conflicts that marked Mormon-Gentile relations over the first seventy years of the church's existence then gave way to the peaceful relations that have existed since. By 1900 the Mormon region as it now exists was basically settled, with the possibility of future expansion limited by the surrounding Gentile settlements.