The U.S. military is ramping up its efforts along the southern border, with the Pentagon announcing the creation of two new “National Defense Areas” (NDAs) in Texas and Arizona. These military buffer zones are designed to enhance national security and support border operations in regions where migration pressures persist.
The newly established NDA in Texas spans 250 miles along the Rio Grande in Cameron and Hidalgo counties. It will now fall under the jurisdiction of Joint Base San Antonio, transitioning from control by the International Boundary and Water Commission. Meanwhile, a 100-mile zone in western Arizona will be linked to Marine Corps Air Station Yuma, although a formal announcement from the Marine Corps is still pending.
This expansion brings the total number of defense areas along the Southwest border to four. Previously, the Department of Defense designated a 63-mile zone connected to Fort Bliss, Texas, and a 170-mile zone tied to Fort Huachuca in New Mexico.
While military personnel in these zones are not acting in a law enforcement capacity, they do have the authority to temporarily detain individuals who cross into these areas illegally, much like on any active military base. These individuals are then transferred to U.S. Customs and Border Protection for processing.
According to a statement from the Air Force, the Joint Task Force–Southern Border, under U.S. Northern Command, will lead operations within these zones. Their role includes monitoring activity via stationary and mobile patrols, detaining trespassers, and installing temporary barriers and signage to secure the areas.
This move signals a heightened collaboration between military and federal agencies in managing border security, as migration, national defense, and public policy continue to intersect in new and evolving ways.
