An internal passport is an identity document that may or may not be used by a country to control and monitor the internal movement and residence of its people. When passports first emerged, there was no clear distinction between internal and international ones. Later, some countries developed sophisticated systems of passports for various purposes and various groups of population. Uses for internal passports have included restricting citizens of a subdivided state to employment in their own area (preventing their migration to richer cities or regions), clearly recording the ethnicity of citizens to enforce segregation or prevent passing, and controlling access to sensitive sites or closed cities.
