The municipality of Athens has an official population of 745,514 with a metropolitan population of 3.8 million (population including the suburbs). The actual population, however, is believed to be higher, because during census-taking (carried out once every 10 years) some Athenian residents travel back to their birthplaces, and register as local citizens there.

Reflecting this uncertainty about population figures, various sources refer to a population of around 5 million people for Athens.[13][14] Also unaccounted for is an undefined number of unregistered immigrants originating mainly from Albania and other Eastern European countries.[15][16]

The ancient site of the city is centered on the rocky hill of the acropolis. In ancient times the port of Piraeus was a separate city, but it has now been absorbed into greater Athens . The rapid expansion of the city initiated in the 1950s and 1960s continues today, because of the transition from an agricultural to an industrial nation.[17]

The expansion is now particularly toward the East and North East (a tendency greatly related to the new Eleftherios Venizelos International Airport and the Attiki Odos, the freeway that cuts across Attica). By this process Athens has engulfed many former suburbs and villages in Attica , and continues to do so.Throughout its long history, Athens has experienced many different population levels. The table below shows the historical population of Athens in recent times.

Year

City Population

Urban Population

Metro Population

1833	4,000	-	-
1870	44,500	-	-
1896	123,000	-	-
1921 (Pre-Population exchange)	473,000	-	-
1921 ( Post-Population exchange )	718,000	-	-
1971	867,023	-	-
1981	885,737	-	-
1991	772,072	-	3,444,358
2001	745,514	3,130,841	3,761,810