More than half a million emigrants struggled westward on the Oregon and California trails. Some were seeking fortune; most were escaping the debt and depression that the Panic of 1837 left in its wake. Few had any grasp of what they were getting themselves into. On their trek to the Pacific slope, these predominantly midwestern farmers and townsfolk—and the animals they took with them—would confront the near-perpendicular walls of box canyons, the jagged calderas of the Snake River Canyon (the trails through which were stained with oxen blood), the dreadful alkali wastes of the Great Basin, the all but impenetrable ravines and saw-toothed ridges of the Wasatch and Blue mountains, and the implacable granite escarpment of the Sierra Nevada.
Fear, hunger, dehydration, heat, cold, monsoonal rains, ravaging mosquitoes, and rapacious traders plagued nearly all of the emigrants. Some overlanders would be killed by Indians; more than a few would wander from their caravans to be lost forever in the endless sea of grass; a far greater number would accidentally shoot themselves—the emigrants, many of whom shot bison with wasteful, nearly sadistic abandon, armed themselves to the teeth, but seemed singularly careless in handling their weapons; still more would be drowned, in the Missouri, the Platte, the Green, the Snake, the Humboldt, and the Columbia rivers, indeed, in virtually every creek or stream the trails traversed. But most of those who died would succumb to diseases, primarily cholera, which devastated entire wagon trains—one emigrant counted 52 graves at a single campsite. The animals suffered far more: while crossing the kiln-dry Forty-Mile Desert, an unavoidable hazard on the trail to California, one diarist counted 9,771 dead horses, oxen, and mules.