Dalmatia, mountainous strip of land, south-eastern Europe, lying almost entirely within Croatia. It extends for about 338 km (210 mi) along the coast of the Adriatic Sea and averages about 56 km (35 mi) in width. It has an area of almost 12,950 sq km (5,000 sq mi) and is traversed by the Dinaric Alps. The crests of submerged mountains form islands in the Adriatic and peninsulas on the coast, which is broken by many inlets and bays. Short rivers, originating in springs in the limestone mountains, east of the coastal area, make precipitous descents to the sea. The Gulf of Kotor on the coast of Montenegro is one of the finest harbours in the world. Split is the region's principal city.

In the 6th century bc, the Greeks established colonies in the kingdom of Illyria, of which Dalmatia then formed a part. When, after many years of fighting, the Romans conquered Illyria in the 1st century ad, the Greek colonies became prosperous Roman municipalities. The Avars, who conquered most of the Dalmatian towns in the 6th century, founded Split. About ad 640 the Croats conquered the Avars; Dalmatia was included in the kingdom of Croatia until 1102, when the latter country was united with Hungary. From 1115 to 1420, Dalmatia was the scene of numerous wars between Hungary and Venice, resulting finally in the subjugation of Dalmatia by the Venetian Republic.

After the fall of the republic in 1797, during the French Revolution, Dalmatia became a Crown possession of the Austro-Hungarian Empire. By the terms of the Treaty of Rapallo (1920), following the defeat of the Central Powers in World War I, Dalmatia was included in the newly created Kingdom of the Serbs, Croats, and Slovenes (which later became Yugoslavia). During World War II, the Italians held a part of the Dalmatian coast from 1941 until 1943-1944, when they were driven out by Yugoslav guerrilla fighters. In 1991, after the constituent republic of Croatia declared its independence from Yugoslavia, the region became a battle zone. Serbs living in Croatia, who preferred that the republic remain part of Yugoslavia, fought against Croatian militias. Serbs controlled parts of Dalmatia until August 1995, when a Croatian offensive drove them from the region.