Adriatic Sea, a large arm of the Mediterranean Sea, extending, in a north-westerly direction, between the east coast of Italy and the west coast of the Balkan peninsula, being terminated to the south by the Strait of Otranto, 45 miles wide. In the north, it forms the Gulf of Venice, and in the north-east, the Gulf of Trieste. The west coast is comparatively low and has few inlets, and the north is marshy and edged with lagoons. On the other side, the coasts of Illyria, Croatia, Dalmatia, and Albania are steep, rocky, and barren, with many inlets, and begirt with a chain of almost innumerable small rocky islands. The total area of the sea, including islands, is calculated at 52,220 sq. m.—the area of the islands being 1290; the mean depth is 110 fathoms, the greatest depth 565 fathoms. The most considerable rivers flowing into the sea are the Adige and the Po, which are continually depositing soil on the coast, so that places once on the shore are now inland. The extreme saltness of the Adriatic is probably owing to the comparatively small quantity of fresh water poured into it by rivers.
Navigation on the Adriatic is safe and pleasant in summer, but in winter the north-east gales (bora) are formidable, on account of the rocky and dangerous coasts on the east. Venice, Trieste, Ancona, Bari, and Brindisi are the chief ports; Brindisi having special importance as the terminus of the railway journey on the shortest Overland Route (q.v.). The fisheries of the Adriatic are rich, and industriously worked.