The circumference of the area is 13 km2 with a population of 72,333 inhabitants. The suburb finds itself at an altitude of 230 meters, 2 km southern of Kifissia, 11 km northeast of Athens center and it is surrounded by the municipalities of Penteli, Vrilissia, Psychiko, Nea Ionia, Heraklion, Halandri, and Pefki.
Marousi, together with the settlements of Halandri, Kalogreza, Penteli, Gerakas, Karystos, Brahami, and Kifissia, was an integral part of the capital of Athens in the first years after the Turkish liberation of the nation, but in 1925 it became a separate community with first president Konstantino Gardeli.
From then until today, it has continuously ascended, succeeding in becoming an important municipality of Attica with distinguished citizens hailing from various scientific and intellectual fields. Among them are the famous singer, Yiannis Kotsiras; the Olympic gold medalist in the first Olympic Games of 1896, Spyros Louis; the Golden Olympic champion, Emilia Tsulfa; and the world-renowned Greek actress and national star of Greece, Aliki Vougiouklaki.