By 1776, the majority of the population in New Mexico identified as mestizo, of mixed Spanish and indigenous ancestry, as interracial marriage between Spanish colonists and indigenous peoples became common. The Spanish explored and settled the Far North of New Spain, now the Southwestern United States, establishing missions to convert indigenous groups to Christianity and exploiting their labor, while trade developed between Spanish settlers and mestizos with Americans arriving after independence through the Chihuahua Trail and later the Adam-Onis treaty.