Arm of the Mediterranean Sea (c.760 km/475 mi long and 97 km/60 mi wide) surrounded by mainland Italy, Sicily, Sardinia, Corsica, and the Ligurian Sea. It is connected to the Ionian Sea through the Straits of Messina. Islands include Elba, Ustica, Capri, Stromboli, and the Lipari Islands. Naples and Palermo are its chief ports. It has a deep seabed plain reaching a maximum depth of 3,620 m/11,876 ft.
The sea contains many submerged volcanic hills, one of which rises some 2,850 m/9,350 ft from the seabed. It was named for the Tyrrhenhoi, an ancient name for the Etruscans.