Indigenous peoples of Mexico
When Mexico gained independence in 1821, the casta system was eliminated as a legal structure, but racial divides remained. 
White Mexican argued about what the solution was to the "Indian Problem", that is indigenous who continued to live in communities and were not integrated politically or socially as citizens of the new republic. The Mexican constitution of 1824 has several articles pertaining to indigenous peoples. The second article of the constitution of Mexico recognizes and enforces the right of indigenous peoples and communities to self-determination and therefore their autonomy to:
American frontier
Mexico became independent of Spain in 1821, and took over Spain's northern possessions stretching from Texas to California. Caravans began delivering goods to Mexico's Santa Fe along the Santa Fe Trail, over the journey which took 48 days from Kansas City, Missouri (then known as Westport). Santa Fe was also the trailhead for the "El Camino Real" (the King's Highway), a trade route which carried American manufactured goods southward deep into Mexico and returned silver, furs, and mules northward (not to be confused with another "Camino Real" which connected the missions in California). A branch also ran eastward near the Gulf (also called the Old San Antonio Road). Santa Fe connected to California via the Old Spanish Trail.