In areas under the exclusive control of non-state armed groups (NSAGs), NSAGs might fill the vacuum left by the State by setting up state-like administration and provide registration services. Legal documentation is necessary to access essential services and rights, such as freedom of movement and access to education or health. This report maps the humanitarian challenges from legal documentation issue under the control of NSAGs – in Central African Republic, Colombia, the post-Soviet space, Sri Lanka, Syria and Iraq, along with mitigating circumstances and strategies.