Abstract Military lands are among the last places most people would list as being pristine. Withdrawn for training and testing, they are tucked away from public exploration, and the results of this isolation have been unexpected: The U.S. Department of Defense (DOD) harbors more rare, threatened, and endangered species on its lands than any other landowner. Despite the vast acreage held in other public ownership, it is the combination of the “tragedy of the commons,” too little funding, and a multi-use mandate that have been the downfall of biodiversity on most non-DOD public lands. Simultaneously, private landowners permanently alter remaining lands at increasing rates. By these processes, the U.S. DOD is now in the position of being capstone stewards. Thus begins an exploration into the question: Does wilderness exist on military installations? In the United States, motorized vehicles are prohibited in federally designated wilderness. On military bases, there are areas where no vehicles may go, such as active air-ground impact areas. If a bomb falls where no tires tread, is it wilderness? The Korean demilitarized zone represents another example of the impact of human conflict and use, or nonuse. Here, the legacy of military actions has unexpectedly created an ecological refuge. Closer to home in the Mojave Desert of California, the juxtaposition of the Marine Corps Air Ground Combat Center and Joshua Tree National Park offers direct comparison between a landscape where people are prohibited and a landscape where people are encouraged. This paper is about the way in which we came to such an unexpected place by examining the trade-off between lands off-limits to civilians, and those where people are encouraged, with the benefits realized from keeping “out,” drawing on examples from the United States and abroad. The objective is to stimulate lively discussion without necessarily coming to a right/ wrong determination or judge whether or not credit is due.