Pike’s expedition, conducted just as Lewis and Clark were returning from their march across the Louisiana Purchase, not only gave the U.S. government new information on the locations of Spanish forts and other details, but it also helped fuel the country’s general expansionist fervor. By the 1840s, “manifest destiny” was the phrase on every American’s lips, and the United States was eyeing the Southwest. It annexed Texas in 1845, but New Mexico, with its small population and few resources, didn’t figure heavily in the short-lived war that resulted—the Mexican governor surrendered peacefully to General Stephen Kearny when he arrived in Santa Fe in 1846. In Taos, though, the transition was not accepted so readily, as a brief but violent uprising instigated by Hispano business leaders with help from Taos Pueblo Indians resulted in the beheading of the first American governor, Charles Bent.

During the Civil War, New Mexico was in the way of a Texan Confederate strategy to secure the Southwest, but the rebels were thwarted in 1862 at the Battle of Glorieta Pass. The territory stayed in the hands of the Union until the end of the war, and people were more concerned with the local, increasingly brutal skirmishes caused by the arrival in Santa Fe of Bishop Jean Baptiste Lamy, a tyrannical—or at least very out-of-touch—Frenchman who tried to impose a European vision of the Catholic church on a populace that had been far beyond centralized control for centuries.

More significant to New Mexico’s development was the arrival of the railroad in 1880, as it was laid through Raton Pass, near Santa Fe, and very close to Albuquerque. Virtually overnight strange goods and even stranger people came pouring into one of the more remote frontier outposts of the United States. Anglo influence was suddenly everywhere, in the form of new architecture (redbrick was an Eastern affectation) and new business. Albuquerque, almost directly on the new railway tracks, boomed, while Santa Fe’s fortunes slumped and Taos all but withered away (its peak had been back in the late days of the Camino Real).

But while wheeler-dealers were setting up shop in central New Mexico, some more intrepid souls were poking around in the less-connected areas farther north. These tourists were artists who valued New Mexico not for its commercial potential but for its dramatic landscapes and exotic populace who seemed untouched by American ways. From the early 20th century on, Santa Fe and Taos were cultivated as art colonies, a function they still fulfill today.