The area does not follow the recommendations of the United Nations regarding urban definitions (i.e. 200 meters between buildings as the required minimum) and is used for statistic issues only.
The main difference between "Hovedstadsområdet" and common urban area definition (or city limits) involves the islands of Amager, Saltholm and Peberholm, and primarily the municipality of Tårnby.
This extended part of Amager is split between Copenhagen and Tårnby municipalities, and is only built-up on two minor areas.
It also includes along the harbour and around Bella Center (which hosted the climate meeting COP 15 in December 2009).
(However the southern part of Amager has agricultural areas and even a small forest, "Kongelunden" ("King's Grove").
In all, most of Tårnby and a minor part of Copenhagen municipalities on Amager island cannot be regarded as an urban area.
But when comparing Copenhagen with other cities, the unpopulated non-urban areas of Amager, Saltholm and Peberholm do make a difference in f.i.
Sometimes in media the word "Hovedstadsområdet" represents a metropolitan area from Køge in the south to Elsinore in the north and Roskilde in the west.