Balkan Peninsula, southeasternmost peninsula of Europe, c.200,000 sq mi (518,000 sq km), bounded by the Black Sea, Sea of Marmara, Aegean Sea, Mediterranean Sea, Ionian Sea, and Adriatic Sea. Although there is no sharp physiographic separation between the peninsula and Central Europe, the line of the Sava and Danube rivers is commonly considered as the region's northern limit. The Balkan Peninsula therefore includes most of Slovenia, Croatia, and Serbia, and Bosnia and Herzegovina, Montenegro, Albania, Macedonia, continental Greece (including the Peloponnesus), Bulgaria, European Turkey, and SE Romania. These countries, successors to the Ottoman Empire, are called the Balkan States. Historically and politically the region extends north of this line to include all of Slovenia, Croatia, Serbia, and Romania.

The peninsula is very mountainous; the main ranges are the Dinaric Alps, the Balkans, the Rhodope Mts., and the Pindus. Except for the barren Karst plateau in the northwest and the eroded highlands of Greece, the mountains are densely forested. The Morava, Vardar, Strimón, Mesta, and Maritsa are the largest rivers. The Morava and Vardar river valleys form the chief corridor across the peninsula. The mild Mediterranean-type climate, with its dry summer period, is limited to the southern and coastal areas. Covering a greater area are the humid subtropical climate in the northwest and the harsher humid continental climate in the northeast. The region as a whole is largely agricultural; fruits, grains, and grazing are important. A variety of mineral deposits are found there, including iron ore, coal, manganese, copper, lead, and zinc.

The peoples of the Balkan Peninsula make up several racial groups. However, linguistic and religious differences are more distinct than the racial divisions. The peninsula, at the crossroads of European and Asian civilizations, has a long history; Ancient Greece, the Byzantine Empire, and the Ottoman Empire flourished there.

or Balkan Peninsula

Peninsula, southeastern Europe. Located between the Adriatic Sea, the Mediterranean Sea, and the Aegean and Black seas, it contains many countries, including Slovenia, Croatia, Bosnia and Herzegovina, Macedonia, Serbia, Montenegro, Albania, Moldova, Romania, and Bulgaria. From 168 BC to AD 107, part of the area was incorporated into Roman provinces, including Epirus, Moesia, Pannonia, Thrace, and Dacia. It was subsequently settled by Slavic invaders, Serbs, Croats, Slovenes, and Slavonized Bulgars, the last of whom were pushed into the Balkan region in the 6th century. It was gradually organized into kingdoms, many of which were overrun by the Ottoman Empire in the 14th–15th century. The factional strife that occurred there from the early 20th century, provoking the continual breakups and regroupings of different states, introduced the word balkanize into English.

Learn more about Balkans with a free trial on Britannica.com.