What is the historical significance of the migration of 12000 Mormons to the Great Salt Lake in 1846?

Many members of the Church of Jesus Christ of Latter Day Saints (LDS or Mormons) fled west to escape religious persecution They arrived in what is now Salt Lake City, UT on July 24, 1847. As a group they made up the largest mass migration in United States history. Their religious persecution is often over looked by history.