MILITARY OPERATIONS BEFORE THE CIVIL WAR The primary mission of
the army in the Southwest was to keep the peace and, in the
event it became necessary, to make war. Essentially, then, in
New Mexico the soldiers provided protection for settlers and
travelers from Indian raiders. Troops stationed at Fort Union
were engaged in such military operations during much of the
history of the post. One consideration in the selection of the
location for Fort Union in 1851 was its proximity to the main
route of the Santa Fe Trail (which in 1851 and after was
sometimes referred to as the "Cimarron Route"), the Bent's Fort
Trail (also known as the Raton Route and, much later, called the
Mountain Route of the Santa Fe Trail),  and the frontier
settlements. The line of communication and supply with the
eastern states was vital to the army and the developing economy
of New Mexico Territory and, of all the military posts
established in the Southwest, Fort Union was the one most
responsible for protecting the mails, government su