WCatholics migrated west to Utah in search of religious freedom

The Mormons.

Explanation:

Mormons are a religious group that believed in Christianity and revelations made by their founder, Joseph Smith. After Smith died, the church divided. Many Mormons followed Brigham Young, who became Smith's successor. Young led a large group of persecuted Mormons from Illinois to search for religious freedom. In 1847, Young and the other pioneers reached Utah's Salt Lake Valley.