Districts of Copenhagen are often based on informal designations based on historic origins, often with alternative names and loosely defined boundaries. Copenhagen Municipality is divided into 10 official administrative districts but they often comprise areas of a heterogeneous character which are informally not seen as one district. Some districts have earlier been official subdivisions and thus have semi-official boundaries. Copenhagen postal code designations often correspond to district boundaries but in some cases differ from them, as an example parts of the city centre has the postal code København V which is generally associated with Vesterbro.