The Adriatic is the sea separating the Apennine peninsula from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges.

The western coast is Italian, while the eastern coast runs along Italy, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, and Albania.

The west shore is generally low, merging, in the northwest, into the marshes and lagoons on either hand of the protruding delta of the river Po, the sediment of which has pushed forward the coastline for several miles within historic times - Adria is now some distance from the shore.

On islands within one of the lagoons opening from the Gulf of Venice, Venice has its unique situation. Other notable cities on the Italian coast are Trieste, Ravenna, Rimini, Ancona, Pescara, Bari and Brindisi.

The east coast is generally bold and rocky, with many islands. South of the Istrian Peninsula, which separates the Gulfs of Venice and Gulf of Trieste from the Bay of Kvarner, the island-fringe of the east coast extends as far south as Dubrovnik.

The islands, which are long and narrow (the long axis lying parallel with the coast of the mainland), rise rather abruptly to elevations of a few hundred feet, with the exception of a few larger islands like Brač (Vidova gora, 778 m) or the peninsula Pelješac (St. Ilija, 961 m). There are over a thousand islands in the Adriatic, 66 of which are inhabited.

On the mainland, notably in the magnificent inlet of the Gulf of Kotor (Boka Kotorska, Bocche di Cattaro; named after the town of Kotor), lofty mountains often fall directly to the sea.

The prevalent colour of the rocks is a light, dead grey, contrasting harshly with the dark vegetation, which on some of the islands is luxuriant. In fact, Montenegro (Black Mountain) was named after the black pines that cover the coast there, and similarly the Greek name for the island of Korčula is Korkyra Melaina meaning "Black Corfu".

Major cities on the northeastern coast include Trieste in Italy; Izola, Koper, Piran and Portorož in Slovenia; Umag, Poreč, Rovinj, Pula, Opatija, Rijeka, Crikvenica, Senj, Zadar, Biograd, Šibenik, Vodice, Primošten, Rogoznica, Trogir, Split, Omiš, Makarska, Ploče, Dubrovnik and Cavtat in Croatia; Neum in Bosnia and Herzegovina; Herceg Novi, Kotor, Tivat, Bar, Budva and Ulcinj in Montenegro; and Durrës in Albania.

Split (Croatia)

Dubrovnik (Croatia)

Zadar (Croatia)

Rijeka (Croatia)

Otok Brač (Croatia)

Koper (Slovenia)

Budva (Montenegro)