The Rise of Military Zones at the Border

The shift began shortly after President Donald Trump’s inauguration in January 2025. A review of federal court data revealed a startling trend: a significant spike in prosecutions for trespassing on military property, far exceeding levels seen in the previous decade. The vast majority of these cases originated along the southern border, coinciding with the White House’s designation of large areas as “national defense areas.”

This designation granted unprecedented authority to troops, allowing them to participate in the apprehension of undocumented immigrants – a role traditionally reserved for civilian law enforcement. More critically, it opened the door to prosecuting individuals under federal laws, including a 1909 statute originally intended to prevent espionage near military installations.

<figure class="wp-block-image size-propublica-position-medium bb--size-medium"><img loading="lazy" height="931" width="752" src="https://www.propublica.org/wp-content/uploads/2026/03/border-defense-area-chart-fallback.png?w=752" alt="A bar chart showing trespass cases from 2016 through 2025. Cases remain very low until mid-2025, when they suddenly spike to nearly 1,000. A label that says, “First national defense area established,” points to the highest point of the spike." class="wp-image-70359" /><figcaption class="attribution"><span class="attribution__caption">Note: Counts are of unique cases in which charges were filed under 50:797 (“Penalty for violation of security regulations and orders”) and 18:1382 (“Entering military, naval, or Coast Guard property”).<br><br>Source: Federal Justice Center’s Integrated Database.</span> <span class="attribution__credit">Agnel Philip/ProPublica</span></figcaption></figure>

<p>The core legal challenge lies in the element of intent. Experts argue that individuals cannot be found guilty of trespassing if they were unaware they were on military land. This is particularly relevant given the often-remote and poorly marked nature of these zones.</p>
<p>Since April of last year, at least 4,700 immigrants facing illegal entry charges have also been hit with these military trespass accusations. Some detainees were held for over a month awaiting trial. Remarkably, 60% of resolved cases resulted in the trespass charges being dropped or dismissed, yet prosecutors continued to pursue them.</p>

<div style="background-color:#fffbe6; border-left:5px solid #ffc107; padding:15px; margin:20px 0;"><strong>Pro Tip:</strong> Understanding the legal definition of "intent" is crucial in these cases. Prosecutors must prove the defendant *knowingly* trespassed, a difficult task when signage is inadequate or nonexistent.</div>

<h2>Challenges in Defining Trespass</h2>
<p>On-the-ground reporting in West Texas and New Mexico revealed the practical difficulties of proving knowing trespass. Language barriers, illiteracy, and the sparse placement of warning signs all contribute to the problem. Many migrants are arrested far from any visible signage.</p>
<figure class="wp-block-image size-propublica-position-medium bb--size-medium"><img loading="lazy" height="501" width="752" src="https://www.propublica.org/wp-content/uploads/2026/03/pratje_probublicanda__005_maxHeight_3000_maxWidth_3000.jpg?w=752" alt="A sign on a post stating in English and Spanish that the area is a military zone, in front of a barren stretch of desert with a small white house." class="wp-image-71980" /><figcaption class="attribution"><span class="attribution__caption">Small signs like this are posted around the national defense areas, but their size and placement often make them difficult to see.</span> <span class="attribution__credit">Paul Ratje for ProPublica and The Texas Tribune</span></figcaption></figure>
<p>A Justice Department spokesperson defended the prosecutions, claiming they deter illegal crossings and disrupt cartel activity. Prosecutors have also argued that the act of crossing the border itself demonstrates criminal intent. However, repeated requests for interviews with senior officials in the U.S. attorney’s offices handling these cases were declined.</p>
<p>Attempts to clarify the boundaries of these zones proved equally frustrating. A ride-along with a Doña Ana County Sheriff’s deputy revealed that even local law enforcement lacked detailed information, relying solely on the placement of small, difficult-to-read signs. Conflicting information was received from Border Patrol and Army personnel regarding the status of a specific parcel of land, highlighting the confusion surrounding these areas.</p>
<p>What responsibility does the government have to clearly demarcate these zones? And how can individuals be held accountable for unknowingly violating laws they were not adequately informed about?</p>
<p>The government has continued to file military trespassing charges in over 1,300 cases since our initial reporting, and has expanded the zones into Arizona, California, and Texas.</p>
<p>You can <a href="https://github.com/propublica/military-trespass/">download the full data used in our analysis</a>.</p>
<p>For further context on border security and immigration policy, see resources from the <a href="https://www.aclu.org/">American Civil Liberties Union</a> and the <a href="https://www.migrationpolicy.org/">Migration Policy Institute</a>.</p>

Frequently Asked Questions About Border Trespass Charges