Until the beginning of the United States’ involvement in the First World War, the military presence was increased by National Guard units mobilized from western states to protect the border. From 1918 to 1933, the border was guarded by African American cavalry and infantry regiments known as “Buffalo Soldiers.”

During the Second World War, airfields established in the region were important training bases. Because of the area’s dry climate, thousands of decommissioned aircraft have been stored here since 1945. Bomber groups and intercontinental missiles deployed here were critical parts of the national defense during the Cold War. Today, Davis-Monthan Air Force Base continues to play an important part in supporting and training U.S. forces and participating in the local economy.

In 1910, when the Mexican Revolution threatened to spill across the U.S. border, Camp Little was established in Nogales. In 1916, this region was a staging area for the Punitive Expedition that crossed into Mexico in pursuit of Pancho Villa after he attacked a town in southern New Mexico.

Read more about Military Posts on the U.S.-Mexico Border.