Porto Torres is a comune and city in the Province of Sassari, northern Sardinia, Italy. It is situated on the north-west coast about 25 kilometres (16 mi) east of the Gorditanian promontory (Capo del Falcone), and on the spacious bay of the Gulf of Asinara. The extension of municipality is almost 10200 hectare and is subdivided in two parts, with almost the same extension. One part includes the city, the industrial area and the Roman ruins; the latter is formed by the Asinara island with the smaller Isola Piana. This part of territory is, since 1997, a national park. The morphology of "city part" is flat; the area of Porto Torres and the rest part of north-west Sardinia is characterized by a Nurra flat, there are some hill formation in the middle of the flat. Part of this hill formation is in Porto Torres' territory and the highest elevation of it is Monte Alvaro with it thickness of 342 m. The communal territory is crossed by two rivers, Rio Mannu and Fiume Santo. The first draws the edge of Porto Torres territory on west, while instead the latter flows near the city and was used as a fluvial way as early as the Roman age.