The town is located on a plateau at about 450 meters above sea level, in a strategic position that has always favoured fruitful exchanges with the nearby towns of Sassari and Alghero. The territory of the municipality, mostly hilly, is not characterised by great elevations, and the altitude varies from a minimum of 74 m above sea level of Rio Minore up to 635 m above sea level of Monte Torru. It is characterised by plateaus mainly consisting of trachytic and basaltic rocks and is crossed by fertile valleys to be cultivated. It borders with Usini, Ossi, Uri, Florinas, Romana, Banari, Bessude, Thiesi, Villanova Monteleone and Putifigari.
The river system in the north is centred on Rio Cuga and its tributaries that flow in the western part of the territory and on Rio Minore, a tributary of Rio Mannu, which takes the names of Camedda and Turighe in the upper part. To the south there is Rio Abialzu that, joining with other smaller rivers, flows towards the catchment of the river Temo. There are two major artificial lakes Cuga and Bidighinzu. The first, fed by rio Cuga-Barca, was built in 1965, is located only partly in the territory of Ittiri and was built for irrigation purposes; the second belongs to the nearby town of Thiesi receiving the waters of Rio Mannu, and was built in 1956 to produce drinking water.
From the point of view of nature it is worth visiting the top of Monte Torru (650 meters) where there is the nuraghe with the same name and which offers a unique panorama that, ranging from Capo Caccia to Asinara, reaches the Gennargentu.