Spain carefully guarded all of its trade routes in the New World, even in a relatively unprofitable territory such as New Mexico. Interlopers were certainly not welcome—only a few enterprising fur trappers, lone mountain men in search of beaver pelts, slipped in. Spy-explorer Zebulon Pike and his crew were captured (perhaps intentionally, so Pike could get more inside information) and detained in Santa Fe [1] for a spell in 1807. But in 1821, Mexico declared its independence from Spain, liberating the territory of Nuevo México along with it—and one of the first acts of the new government was to open the borders to trade. Initially just a trickle of curious traders came down the rough track between St. Louis and Santa Fe [1], but soon a flood of commerce flowed along the increasingly rutted and broadSanta Fe Trail, making the territory’s capital city a meeting place between Mexicans and Americans swapping furs, gold, cloth, and more.
Links:
[1] http://www.moon.com/destinations/santa-fe-taos-albuquerque/santa-fe