Why did mountain men move west to find beaver furs?

Mountain men moved west to find beaver furs primarily due to the high demand for beaver pelts in the fashion industry, particularly for making hats in Europe and America. The fur trade was lucrative, and the Rocky Mountains offered abundant beaver populations and untapped resources. Additionally, the westward expansion during the 19th century provided opportunities for adventure, exploration, and potential wealth in a largely uncharted territory. The combination of economic incentives and the allure of the frontier motivated these trappers and traders to venture into the wilderness.