Camp Naco Historic District

The formal establishment of a defined border between the U.S. and Mexico followed the Treaty of Guadalupe-Hildago in 1848 and the Gadsden Purchase in 1854. Upon the U.S. acquisition of the Southwest, the biggest threat to American expansionists' interests came from the Apache. Much as the Spanish had done less than a century before, the U.S. government sought to protect its interests by establishing military posts throughout its southern borders. In Arizona, military posts were initially established to protect ranchers and miners from Apache depredations, but once the Apache were subdued, military efforts shifted to patrolling the U.S-Mexico border and protecting the additional interests of the transcontinental railroad and homesteaders. In consequence, many of these military compounds were discontinued.

Even though the Apache were no longer a serious threat, other threats to U.S. sovereignty emerged. In 1910, the Mexican Revolution erupted and the U.S. government grew increasingly concerned that the conflict would spill over the border into the United States. In an effort to protect American interests and preserve "neutrality laws" threatened by unrest in Mexico, military troops were once again sent to protect the border. During this time, 35 military camps were established along the U.S.-Mexico border, stretching from Brownsville, Texas to Arivaca, Arizona. These posts, and the soldiers who occupied them, later served as part of a 1,200-mile-long border "fence" along the southern United States. By 1919, over 30,000 American troops were positioned along the country's southern border. One of these, Camp Naco, was located in the border town of Naco, Arizona.

The town of Naco had a military presence from 1911 until the end of 1923, with troop strength ranging from 50 to over 5,000. In 1919, Camp Naco became a permanent military post, when 35 buildings and associated structures replaced the former tent community at the town site of Naco. Unlike the other 34 Mexican Border Defense posts of this era, Camp Naco was only one of two posts utilizing adobe construction (Camp Furlong in Columbus, New Mexico also utilized adobe construction in its border camp, but it predates the Mexican Border Defense Construction Project). Moreover, while the War Department stationed many different units at the townsite of Naco, the longest serving units were the Ninth and Tenth Cavalry Regiments, and later the Twenty-fifth Infantry Regiment; all Buffalo Soldier (African American) units. Today, Camp Naco remains the only standing example of the Mexican Border Defense Construction Project fortifications in Arizona still possessing a high degree of historical integrity. Moreover, Camp Naco is one of the best-preserved examples of the continued militarization of the borderlands and remains one of the best-preserved Mexican Border Defense Construction Projects in the United States. It is also only one of two such fortifications that utilized adobe construction, remaining the most complete example of a Twentieth-century adobe border fortification.