Exposed to the wind, within a sweeping valley of short grass prairie, amid the swales of the Santa Fe Trail, lie the territorial-style adobe remnants of the largest 19th century military fort in the region. For forty years, 1851-1891, Fort Union functioned as an agent of political and cultural change in New Mexico and throughout the Southwest. Fort Union was established in July, 1851, several miles north of the junction of the two main branches of the Santa Fe Trail. Several reasons are commonly given for its establishment including a desire on the part of the new district commander, Colonel Edwin V. Sumner, to remove the troops from the *morally degrading* influences of Santa Fe. The most likely reason was economics, however, and Sumner moved numerous New Mexico garrisons out of leased quarters and directed that self-sufficient operations, such as troop-constructed buildings and post farms be initiated. Problems with Comanche, Ute, and Jicarilla Apache tribesmen along the southern-most reaches of the Trail constituted another reason for a post away from the Sangre de Cristos and out on the Great Plains. From such a point, troops could more readily patrol the area and react to trouble in a more timely manner than had been the case. The general area encompassing Fort Union National Monument has been used historically by travelers along what would become the Santa Fe Trail. They include various American Indian groups of several different tribes, Spanish explorers and settlers, New Mexicans both travelling through the area and using it for grazing for both sheep and cattle, Frenchmen seeking riches in Santa Fe and New Mexico, Americans benefitting from trade with New Mexico, an army of invasion, civilian and military personnel associated with the three Fort Unions and the Santa Fe Trail, and ranchers. The reason for the existence of Fort Union arises from the Santa Fe Trail, whose ruts radiate north and south of the Forts. Indeed the area has long been an area traversed by people. Perhaps the earliest travellers were Pueblo Indians who travelled east over the Sangre de Cristo Mountains and down along the Mora River, out to the plains to hunt buffalo and trade with the plains tribes. A pueblo type structure has been found along the Mora River near Watrous which dates to circa 1200 indicating that at least one Indian dwelling was nearby.