Some American neighborhoods are so volatile that even law enforcement considers them high-risk zones. While “cop-free zones” are rarely official designations, crime data, community studies, and on-the-ground reporting suggest there are areas where police make limited foot patrols, face threats, or handle calls with extreme caution. For U.S. readers curious about urban safety realities, here are 15 neighborhoods that experts and community voices say are particularly dangerous — and in many cases, deeply challenging for officers to operate in.