Reasons why: The members of the Church of Jesus Christ of Latter-day Saints were persecuted for their beliefs. Along with Anti Mormon prejudice starting angry mobs
Crossing the frozen Mississippi in subzero temperature was a challenge. Also Young the new leader had little knowledge of the geography and environment of the West and no particular destination in mind, but trusting in God.
The Mormons settled in Utah beside the Great Salt Lake. They begin building a new civilization in the valley. In 1877 more than 100,000 people were living in the surrounding Great Basin