Monte Mario is the hill that rises in the north-west area of Rome, on the right bank of the Tiber, crossed by the Via Trionfale. It occupies part of Balduina, of the territory of Municipio Roma I, of Municipio Roma XIV and a small portion of Municipio Roma XV of Rome, thus including part of the Quarters Trionfale, Della Vittoria and Primavalle.
The same toponym also identifies the urban area which extends over the hill, close to Via Trionfale and the first stretch of Via di Torrevecchia, with the railway station of the same name.
It is the highest hill in the town and, together with the Janiculum and the Pincius, one of the most scenic spots in the city, especially in the place called "Zodiac", which offers a south and west view of the main architectural monuments of the city, of the Vatican City, of the Alban Hills, of the Monti Tiburtini, of the Monti Prenestini and of the highest peaks of western central Apennines. Here, moreover, begins the longest Linear Park in Rome, which connects the town to the Parco di Monte Ciocci.
The location has been chosen as trigonometrical station in the Gauss–Boaga cartographic projection, giving rise to che datum Roma 40.