The '''Athens Metropolitan Area''' () spans  within the Attica region and includes a total of 58 municipalities, which are organized in seven regional units (those outlined above, along with East Attica and West Attica), having reached a population of 3,737,550 based on the preliminary results of the 2011 census. Athens and Piraeus municipalities serve as the two metropolitan centres of the Athens Metropolitan Area. There are also some inter-municipal centres serving specific areas. For example, Kifissia and Glyfada serve as inter-municipal centres for northern and southern suburbs respectively.