stylistic:tone, structural:scholar_edition
Geography

The Adriatic Sea is a semi-enclosed sea, bordered in the southwest by the Apennine or Italian Peninsula, in the northwest by the Italian regions of Veneto and Friuli-Venezia Giulia, and in the northeast by Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, and Albania —the Balkan peninsula. In the southeast, the Adriatic Sea connects to the Ionian Sea at the 72-kilometre (45 mi) wide Strait of Otranto. The International Hydrographic Organization (IHO) defines the boundary between the Adriatic and the Ionian seas as a line running from the Butrinto River 's mouth (latitude 39°44'N) in Albania to the Karagol Cape in Corfu, through this island to the Kephali Cape (these two capes are in latitude 39°45'N), and on to the Santa Maria di Leuca Cape (latitude 39°48'N). It extends 800 kilometres (500 mi) from the northwest to the southeast and is 200 kilometres (120 mi) wide. It covers 138,600 square kilometres (53,500 sq mi) and has a volume of 35,000 cubic kilometres (8,400 cu mi). The Adriatic extends northwest from 40° to 45° 47' north, representing the Mediterranean 's northernmost portion. The sea is geographically divided into the Northern Adriatic, Central (or Middle) Adriatic, and Southern Adriatic.

The Adriatic Sea drainage basin encompasses 235,000 square kilometres (91,000 sq mi), yielding a land–sea ratio of 1.8. The drainage basin's mean elevation is 782 metres (2,566 ft) above sea level, with a mean slope of 12.1°. Major rivers discharging into the Adriatic include the Po, Soča, Krka, Neretva, Drin, Buna, and Vjosë. In the late 19th century, Austria-Hungary established a geodetic network with an elevation benchmark using the average Adriatic Sea level at the Sartorio pier in Trieste, Italy. The benchmark was subsequently retained by Austria, adopted by Yugoslavia, and retained by the states that emerged after its dissolution. In 2016, Slovenia adopted a new elevation benchmark referring to the upgraded tide gauge station in the coastal town of Koper.

The Alps, which also have a large meteorological impact on the Mediterranean, touch the Adriatic in the area around Trieste towards Duino and Barcola.

The Adriatic Sea contains more than 1,300 islands and islets, most along the Adriatic's eastern coast—especially in Croatia, with 1,246 counted. The number includes islands, islets, and rocks of all sizes, including ones emerging at ebb tide only. The Croatian islands include the largest— Cres and Krk, each covering about the same area of 405.78 square kilometres (156.67 sq mi) —and the tallest— Brač, whose peak reaches 780 metres (2,560 ft) above sea level. The islands of Cres and the adjacent Lošinj are separated only by a narrow navigable canal dug in the time of classical antiquity; the original single island was known to the Greeks as Apsyrtides. The Croatian islands include 47 permanently inhabited ones, the most populous among them being Krk, Korčula and Brač. The islands along the Adriatic's western (Italian) coast are smaller and less numerous than those along the opposite coast; the best-known ones are the 117 islands on which the city of Venice is built. The northern shore of the Greek island of Corfu also lies in the Adriatic Sea as defined by the IHO. The IHO boundary places the Diapontia Islands (northwest of Corfu) in the Adriatic Sea.