Definition: Geographic hierarchy
UN - Geographic Information Systems
In the context of census-mapping, a system of usually nested area units that are designed for administrative or data-collection purposes. For instance, a country is divided into provinces, which are divided into districts and so on to the lowest level, which may be the enumeration area. See also "Census geographic framework".
United Nations, "Handbook on Geospatial Infrastructure in Support of Census Activities", Department of Economic and Social Affairs, Statistics Division, Studies in Methods, Series F No. 103, New York, 2009