Geography and extent

Physiographically, Europe is the northwestern constituent of the larger landmass known as Eurasia, or Africa-Eurasia: Asia occupies the eastern bulk of this continuous landmass (save the Suez Canal separating Asia and Africa) and all share a common continental shelf. Europe's eastern frontier is now commonly delineated by the Ural Mountains in Russia (Strabo, Geography 11.1, took the Tanais River to be the boundary, as did early Judaic sources). The southeast boundary with Asia is not universally defined. Most commonly the Ural or, alternatively, the Emba River serve as possible boundaries. The boundary continues to the Caspian Sea, the crest of the Caucasus Mountains or, alternatively, the Kura River in the Caucasus, and on to the Black Sea; the Bosporus, the Sea of Marmara, and the Dardanelles conclude the Asian boundary. The Mediterranean Sea to the south separates Europe from Africa. The western boundary is the Atlantic Ocean; Iceland, though nearer to Greenland (North America) than mainland Europe, is generally included in Europe. There is ongoing debate on where the geographical centre of Europe is. For detailed description of the boundary between Asia and Europe see transcontinental nation.

Due to sociopolitical and cultural differences, there are various descriptions of Europe's boundary; in some sources, some territories are not included in Europe, while other sources include them. For instance, geographers from Russia and other post-Soviet states generally include the Urals in Europe while including Caucasia in Asia. Numerous geographers consider Azerbaijan's and Armenia's southern border with Iran and Turkey's southern and eastern border with Syria, Iraq, and Iran as the boundary between Asia and Europe. Similarly, the island of Cyprus, though closest to Turkey (Asia Minor), is frequently included in Europe.

In another usage, Europe is increasingly being used as a short-form for the European Union (EU) and its members, currently consisting of 27 member states and the candidate countries negotiating for membership, and several other countries expected to begin negotiations in the future (see Enlargement of the European Union). This definition, however, excludes non-members such as Switzerland, Norway and Russia.