The Caucasus or Caucasia is a region spanning Europe and Asia bordered on the north by Russia, on the east by the Caspian Sea, on the south by Iran, on the southwest by Turkey, and on the west by the Black Sea. Caucasia includes the Caucasus Mountains and surrounding lowlands.
The Caucasus Mountains are commonly recognised as a natural border between Asia and Europe. Countries in the Caucasus are considered to be in one or both continents, with Armenia and Azerbaijan considered transcontinental, and Georgia largely considered European. The northern portion of the Caucasus is known as the Ciscaucasus and the southern portion as the Transcaucasus. The highest peak in the Caucasus is Mount Elbrus (5,642 m) which, in the western Ciscaucasus in Russia, is generally considered the highest point in Europe.