What was the Mormon trip to Salt Lake City?

The Mormons were settled in Nauvoo, Illinois on the banks of the Mississippi river. They were then forced to leave in 1846, essentially the then United States and travel to what is now Utah. Brigham Young, the prophet at the time, led them there, as he saw in a vision the place where they were to go and flourish, as they did in Utah. They reached the Salt Lake valley in 1847.