The province was divided into two administrative districts: the Río Arriba and the Río Abajo, which referred to the upper and lower portions of the Río Grande Valley and the adjacent districts. From Santa Fe, located in central New Mexico and at the center of the Pueblos, Spanish governors managed the affairs of the province until 1821, when Mexico gained its independence from Spain. Earlier, near the end of the seventeenth century, the Pueblos revolted and routed the Spaniards for approximately a decade. The Reconquest of 1692, by Governor Vargas, restored the regime of the Spaniards.
In August 1846, during the Mexican-American War, U.S. Colonel Stephen Watts Kearney took formal possession of New Mexico and granted citizenship and amnesty to anyone swearing allegiance to the United States. Over the next several decades, both Mexicans and Indians struggled to survive within the bowels of the new nation that conquered them.
Development of the region in the second half of the nineteenth century proceeded quickly under the influence of the Santa Fe Ring, a group of American bankers, lawyers, merchants, and politicians who promoted their interests in the region. Landgrabbing became one of the most lucrative activities among the members. In 1880, the railroad reached Albuquerque, and the following year, the Atlantic & Pacific Railroad and the Southern Pacific met at Deming, New Mexico. The region's population tripled over the next two decades as Americans migrated into the area in search of lands to mine, graze, and farm. Cattle barons on the eastern New Mexico plains provided beef on the hoof to Indians on reservations and soldiers at American military outposts.
