The Mormon migration was organized with considerable sophistication. Young established a system of coordinated wagon trains, supply caches, and communication that allowed tens of thousands of people to make the crossing over several years. The Smith family’s conversion in 1847 and their decision to join the exodus placed them within this organized migration infrastructure.
For the enslaved people in Smith’s household, the organized nature of the migration meant something specific: they were embedded in a large social structure with its own hierarchy, rules, and mutual obligations, but those obligations ran among the white converts, not to or from the enslaved people who accompanied them. Brigham Young had, by some accounts, warned the Mississippi Saints that enslaved people could not legally be held in Utah Territory under the same terms as in a slave state, though Utah was organized as a territory with a more ambiguous status on slavery. Smith proceeded regardless.
The 1848 departure from Winter Quarters, Nebraska, on July 3 placed the Smith party at the beginning of one of the more demanding overland routes in North American history. The road to the Salt Lake Valley crossed the Platte River valley, the Wyoming high plains, the Continental Divide at South Pass, and then descended through increasingly difficult terrain toward the Great Basin. The journey was approximately 1,700 miles and took several months.
The specific role Biddy Mason played on this journey is documented in sources that are largely retrospective — accounts written or compiled years or decades after the events they describe. But the accounts are consistent: she walked at the rear of the caravan, herding livestock. This positioning was not incidental. The livestock were essential property: cattle, sheep, and other animals represented significant capital investment and future productive capacity in the new settlement. The person assigned to herd them was responsible for keeping them moving, keeping them from straying or being lost, and managing them through the various hazards of the trail — river crossings, rough terrain, encounters with the herds of bison that still populated the central plains.