Final answer:
The Main Route of the Old Spanish Trail took a more northern path through central Utah to provide safer travel, better water sources, and grazing land, and to avoid the deserts of Nevada. This path also aligned with the Mormon settlement near the Great Salt Lake and reflected possible cultural or religious beliefs similar to those of the Pueblo peoples. Trade, migration necessity, seasonal timing, and safety factors significantly influenced the trail's direction.
Step-by-step explanation:
The Main Route of the Old Spanish Trail did not travel straight between New Mexico and southern California due to a combination of historical, geographical, and cultural factors. As settlers, travelers, and later the Mormon pioneers moved westward, they sought routes that provided safer travel, sufficient water, and grazing lands for livestock, even if that meant a more northerly trajectory into central Utah. The journey through Utah also avoided the harsh deserts of Nevada, which presented a significant barrier in terms of water scarcity and difficult terrain.
Additionally, after the Mormon migration under Brigham Young in the aftermath of Joseph Smith's death, the Mormons settled in a region near the Great Salt Lake in what was then Mexico, later becoming the United States after the Treaty of Guadalupe Hidalgo. Young's appointment as territorial governor and the settlement's establishment as part of the United States influenced trail routes to include Utah more directly. The orientation of the trail also suggests some cultural or religious significance, echoing Pueblo beliefs where certain roads lead to areas of religious meaning, as in the case of the North Road leading to the sipapu. Nonetheless, trade and migration needs were paramount, shaping the trail to traverse environments that were more conducive to the survival and progress of the travelers.
This is evident in the broader context of trail development during westward expansion, with trails such as the Oregon Trail, California Trail, Mormon Trail, and Bozeman Trail branching off based on conditions and destinations. Additionally, the necessity for coordination and safety among migrating groups, the susceptibility to diseases, and the importance of timing and season also played a significant role in determining the routes of these trails, including that of the Old Spanish Trail.