After the Mormons were forced out of Nauvoo, Illinois, in 1846, many temporarily settled around Kanesville (now Council Bluffs), Iowa. The first Mormon pioneers founded Salt Lake City in 1847, but five years later, many thousands of Mormons were still in Iowa, trying to collect resources to make the long trek across the Great Plains. They lacked food, wagons, and other supplies they would need.
In 1852, the First Presidency sent Elder Ezra T. Benson to organize the scattered Saints into wagon trains. Benson was successful in sharing the message of urgency in gathering, and most of the Saints made the trek that summer, in more than twenty-five companies. This article identifies five factors that led Church leaders to push the stragglers to Utah in 1852, causing the busiest year of the Mormon Trail.
Hartley, William G.
"The Closedown of LDS Iowa Settlements in 1852 That Completed the Nauvoo Exodus and Jampacked the Mormon Trail,"
BYU Studies Quarterly: Vol. 52
, Article 5.
Available at: https://scholarsarchive.byu.edu/byusq/vol52/iss3/5