Between 1847 and 1869, thousands of Mormons crossed the plains making their way to Utah Territory. While a good number of these immigrants were Americans, another significant portion were converts from a variety of countries around the world. These men and women had been converted to Mormonism in their native countries and later made the decision to gather in Utah with others of similar beliefs, both to build the church there as well as to avoid persecution in their homelands. Some of the largest groups of immigrants making the trek were from Scandinavia and England; however, points of origin included Australia and South Africa.
If you believe that one of your ancestors may have been one of the brave pioneers making that journey, your first step is to identify the ancestor. When researching information about families during this time keep in mind that family names often had a variety of spelling variations. This was particularly true among Scandinavian immigrants. In addition, keep in mind that in some cases, children traveled with grandparents, aunts, uncles, siblings, etc. In these cases, they may have traveled with someone with a different surname. After you have identified as much information as possible about the ancestor, including their country of origin, your next step is to identify their date of emigration from that country to the United States. The span of time during which they may have traveled is broad, so it is best o narrow it down as much as possible.
After you have determined the ship by which they traveled and the date of the arrival in the United States, the next step is to begin identifying the dates during which they make the journey over the Mormon trail. The book, Mormon Pioneer Companies Crossing the Plains, is an excellent resource when researching this type of information. Keep in mind that there were numerous companies of immigrants who made their way over the trail during the 20+ years that Mormons primarily migrated to Utah through an overland trail; however, if you have narrowed down the dates, the search will not be as exhaustive.
It is also a good idea to make sure that you verify the name of your ancestor against the census rolls as well as the pioneer company rosters as well. For the most part, individuals listed on the Utah census for the years 1850 and 1860 as well as most on the 1870 census were immigrants.