In August 1846, a U.S. military force invaded the Republic of Mexico from this area, where the international boundary then lay at the Arkansas River about 80 miles north. The U.S. Army of the West moved through Mexican territory with 1,600 troops, 1,500 supply wagons and field pieces, 15,000 oxen, 4,000 mules, and uncounted teamsters, muleteers, and drovers, beginning the struggle up and over Raton Pass. Colonel Stephen W. Kearny took a daring gamble, because until then only a few freight wagons had been hauled laboriously over the pass. Without firing a shot, Kearny went on to occupy Mexico's territorial capitol of Santa Fe. Later, promoted to general, he marched his army to California, helping subdue that Mexican territory while other U.S. armies invaded farther south and occupied Mexico City, where the U.S. Marines stormed the Halls of Montezuma. When the war ended in 1848, Mexico ceded about half of Colorado, including this spot, most of New Mexico and Arizona, and all of California, Nevada, and Utah to the United States. At the time of the war, the Santa Fe Trail passed through this point, but the town of Trinidad did not develop until the 1860s.