This is a list of all the urban areas of the European Union which have greater than 500,000 inhabitants each in 2014. This list is an attempt to present a consistent list of population figures for urban areas in the European Union. All the figures here have been compiled by Demographia.
This is a list of urban areas, not a list of metropolitan areas. Urban areas are contiguous built-up areas where houses are typically not more than 200 m apart (discounting rivers, parks, roads, industrial fields, etc.). A metropolitan area is an urban area plus the satellite cities around the urban area and the agricultural land in between.
This is a list of urban areas, not a list of administrative cities. For example, the list below contains the urban area of Lille-Kortrijk. Lille and Kortrijk remain two very distinct cities, each belonging to a different country, culture and language area. For a list of the largest cities of the European Union by population, please see Largest cities of the European Union by population within city limits.
The study of urban areas is useful to analyse how cities develop, which in turn can be used to define transportation, planning and environmental policies, to adjust administrative boundaries etc. At the same time its limitations have to be acknowledged. It is a purely geographic study and disregards all other factors that contribute to the analysis of the functional city. For instance, several cities in the European Union such as Brussels and London have introduced green belts which impacts the urban area but not the "perceived city" as these green belts have now become integrated in what people consider to be the functional city. Furthermore the list does not make a difference between cities that have multiple satellites and cities that do not. Therefore two cities with the same demographics for their urban area will have an equal ranking on this list, even if one of the two cities may be much larger as it is the core of a number of satellites.
If you are used to higher figures for the cities listed below (London is sometimes listed with 14 million inhabitants, Stuttgart is frequently listed with 2.2 million inhabitants, Munich with 2 million or more, etc.), this is because figures here are only for urban areas, which are typically smaller than metropolitan areas. Urban areas can be computed by private people or institutions using maps and looking where the built-up area stops. Metropolitan areas, which imply much more complicated definitions (such as the proportion of people in satellite cities working in the core of the metropolitan area), can be accurately computed only by statistical offices, after they have chosen a definition for metropolitan areas.