--- title: "The military really wants people to stop trespassing on its test range in the desert" description: "Army officials said off-roaders drive onto the desert range mostly by accident, but they could be injured by unexploded ordnance." date: "2026-02-12" modified: "2026-02-12" authors: - name: "Patty Nieberg" job_title: "Senior Reporter" link: "https://taskandpurpose.com/authors/patty-nieberg/" url: "https://taskandpurpose.com/news/army-yuma-proving-ground-trespassers/" categories: - "News" --- # The military really wants people to stop trespassing on its test range in the desert ![U.S. Marines with 3d Low Altitude Air Defense Battalion, Marine Air Control Group 38, 3d Marine Aircraft Wing (MAW), sight in on a simulated FIM-92 Stinger surface-to-air missile while on a Forward Arming and Refueling Point at U.S. Army Yuma Proving Grounds, Yuma, Arizona, May 23, 2022. The weapons configuration consists of six inert guided bombs, four mounted onto the wings and two loaded into the weapons bay, as well as an Air Intercept Missile 9X. Marine Aircraft Group 13 forces are capable of conducting offensive air support, anti-aircraft warfare, and aviation reconnaissance from expeditionary sites in any clime and place. (U.S. Marine Corps photo by Sgt. Samuel Ruiz)]() *Base officials said off-roaders drive onto the desert range mostly by accident, but they could be injured by unexploded ordnance. Marine Corps photo by Sgt. Samuel Ruiz.* You would think it’s easy to keep people from wandering across barren stretches of wasteland littered with unexploded ordnance, but apparently that’s not the case for a military test range in the Arizona desert, especially during peak tourist season. Yuma Proving Ground police have had to crack down on trespassers on the 1,300-square-mile range, where the services test their latest experimental tech and regularly conduct [live-fire training exercises]() — both of which are inherently dangerous and make it a less-than-ideal place to meander aimlessly. Officials said in a [press release]() that “instances of trespassing have been stubbornly persistent in recent years.” “After more than 80 years of existence and plenty of posted no trespass signs, you might think people would steer clear of these areas. But you would be wrong,” [reads the release](). The [Army traces its roots]() to the area as far back as 1850, but the site has been a formal training area for all the services since World War II, when troops rotated through before heading for combat in the North African deserts. After the war, the military continued to use the land for testing aircraft, munitions, armed helicopters, and precision navigation tech. Nowadays, the services conduct [routine training]() in the desert landscape, and regularly use it to test defense tech like counter-drone weapons and high-tech lasers, which officials noted can cause “serious eye injuries” to unwary trespassers. Mark Schauer, a spokesman for the Army Test and Evaluation Command, which manages the range, said a “significant majority” of range trespassers are winter visitors who come to the area and are “off-highway vehicle enthusiasts.” Due to the size of the Proving Ground, however, “it would not be feasible to fence all of it off,” he said. The press release was put out ahead of President’s Day weekend, when tourism is high and Yuma’s population “roughly doubles in winter,” Schauer said. Sgt. Gregory Harper, a conservation law enforcement officer at Yuma Proving Ground, said in the release that he mostly runs into “genuinely good people,” who “are cooperative and their intent isn’t bad, but that won’t protect them from the hazards on our ranges.” Throughout his career, Harper has had to pull people out of abandoned mines. In 2024, he joined multiple law enforcement agencies in a 12-hour [rescue mission of a woman who broke her ankle at the bottom of a 200-foot-deep mine shaft](). Schauer noted that the 2024 incident happened about a mile and a half outside of the Yuma Proving Ground border, but there are abandoned mines all across the range. The Defense Department estimates that it’ll cost $45 million to clean up dozens of sites with unexploded ordnance on Yuma by 2045, according to [ProPublica reporting](). ## Author Patty is a senior reporter for Task & Purpose. She's reported on the military for six years, embedding with the National Guard during a hurricane and covering Guantanamo Bay legal proceedings for an alleged al Qaeda commander. Her previous bylines can be found at the *Associated Press*, *Bloomberg Government*, *Washington Post*, *The New York Times*, and *ABC*. You can reach Patty by email at [Patty.Nieberg@taskandpurpose.com](). ### Author social links [Twitter]() [LinkedIn]()