Geographically, the Ager Romanus (Italian - Agro Romano) is the name given to the immense rural area (part plains, part hilly) around the city of Rome. Politically and historically, it has represented the area of influence of Rome's municipal government. It is delimited to the south by Monti Prenestini, by the Alban hills and the pianura pontina; to the west by the Tyrrhenian Sea; to the north by the hills surrounding Lago di Bracciano and to the east by the Monti Tiburtini.