The mountain men initially began exploring the western portion of North America in search of fur, then turned their attention to exploring trails for masses migrating from the East. The first mountain men prospered as trappers and fur traders in central Canada and the United States, but faced dwindling animal populations by the beginning of the 19th century. Lured by the writings of Lewis and Clark, many of these men headed westward in search of larger animal populations.
These explorations proved lucrative for the next 30 years until over-hunting reduced animal populations and the consumer demand for silk replaced the demand for furs. With few reasons to return East, many mountain men served as army scouts and guides, becoming familiar with the region and the local natives. The discovery of gold in California and later in Alaska, silver in Nevada and Colorado and the exodus of Mormons to Utah resulted in a steady migration of settlers from the East who needed routes to the west that they could travel with some degree of ease and safety. From this point, the mountain men’s exploration of the West revolved around finding trails and passages that the settlers could negotiate with wagons and remain relatively safe from Indian attacks.