The Province of Rome covers almost one-third of the territory of Lazio. It occupies the flat area of the Roman and the Tiber Valley to the mountains and dell'Aniene Lucretili Sabini and, in addition to the mountainous regions of the Tolfa and Monti Sabatini to the north-west, the area of the mountains Tiburtini Prenestini Simbruini and east, the area of the Colli Albani and the northern foothills of the mountains, and high Lepine Sacco valley to the south-east. The western boundary of the province is represented by the Tyrrhenian Sea on which spread to about 130 km from the coast near Rome from Civitavecchia to Torre Astura. In the territory there are several lakes, almost all of volcanic origin, which are concentrated in the north-west of the mountains and Sabatini in the south-east of the Colli Albani.
The main comuni by population are:
|Genzano di Roma||24,008|
- "Demography in Figures". Istituto nazionale di statistica (ISTAT). for August 2009