以洛杉矶举例,城市辖区(City of Los Angeles)的人口是390万,市区/建成区(Urban)是1215万,都会区(Metropolitan)是1310万(包括了如文图拉县、洛杉矶县、橙县等县份但不包括圣迭戈都会区),CSA人口则高达1820万人,因为CSA包含洛杉矶和圣迭戈两大都会区。
^2011 Census: Characteristics of Built-Up Areas. Office for National Statistics. 2013-06-28 [2019-10-20]. (原始内容存档于2021-01-18). Built-up areas are defined as land which is ‘irreversibly urban in character’, meaning that they are characteristic of a village, town or city. They include areas of built-up land with a minimum of 20 hectares (200,000m2). Any areas with less than 200 metres between them are linked to become a single built-up area.