In the mid-1800s, persecution against Mormons in the east and mid-west was so bad that they had been forced to move their headquarters four times in 15 years. Sometimes these moves were due to mob violence, and other times at the urging of local governments. After their prophet, Joseph Smith, was murdered and the government of Illinois asked them to leave, the Mormons yet again sought a place where they could practice their religion in peace.
Since the US federal government said they would do nothing to help, the Mormons turned to Mexico and travelled to the Great Salt Lake. Only a few years later, this land became part of the United States due to the Mexican-American War.
However, by this time the Mormons had established themselves and found a land where they could practice their religion. For the next 50 years, Mormons living outside of the western United States were encouraged to "gather to Zion" by moving closer to Utah. This was mostly a way to keep unity within the church, as long distance communication was difficult.
Because they were being killed and harassed, and because they were directed to do so by God through his prophet.
Utah.
Utah was settled by Mormons.
The signifigence of the Mormons moving west was for them to escape religious percsecution
The Mormons were searching for a place where they could practice their religion in peace and found that place in Utah.
Mormons traveled west in either a conestoga wagon or handcart and settled in Utah.
The Mormons were seeking religious freedom. They had been harrassed and kicked out of previous settlements in Ohio, Missouri, and Illinois, so they went west to leave the United States (because at that time the area that is now Utah was part of Mexico).
Mormons settled much of the west. Church headquarters was built in Salt Lake City, but hundreds of towns all over Utah, Idaho, Wyoming, Arizona, Nevada, and California were settled by Mormons.
Many of what are now the Western United States were settled by "Mormons." You may be referring to Utah, however, which was the primary destination of the move west.
Mormons began traveling west in 1831, moving from New York to Ohio. They then moved to Missouri, Illinois, and then what is now Utah. This is because each place they attempted to settle, they faced brutal persecution and in some cases were kicked out of their homes. They left to a place that was uninhabited so that they could practice their religion in peace.
The Church of Jesus Christ of Latter Day Saints (commonly called the "Mormons") migrated west and settled in what is now Utah (along with parts of Idaho, Arizona, Wyoming, and Nevada) and which then was part of Mexico. They arrived in 1847 and are still the dominant religious group in the area today.
The Mormons were receiving massive persecution, being moved from New York to Kirtland, to eventually Utah. So basically, they wanted a place to worship their religion in peace
Joseph Smith did not lead the Mormons to Utah at all. Joseph Smith was murdered in Illinois a year before the first group set out for the west. He did prophesy that eventually they would move to the Rocky Mountains, but he never did anything to lead them there.