who is a transcontinental Eurasian country .
The modern border follows the Aegean Sea , the Dardanelles - Sea of Marmara - Bosphorus , the Black Sea , along the watershed of the Greater Caucasus , the northwestern portion of the Caspian Sea and along the Ural River and Ural Mountains to the Arctic Ocean , as mapped and listed in most atlases including that of the National Geographic Society and as described in the World Factbook .