The Caspian sea forms Azerbaijan's eastern border.
Asia is completely to the east of Europe, so any border will be the part of the eastern border. The Ural & Caucus Mountains form the eastern border as well as the Bosphorus Strait and part of the Mediterranean Sea and Caspian Sea.
Azerbaijan is not a body of water. It's a country on the border of the Caspian Sea. Azerbaijan is in Europe and Aisa.
Europe shares its eastern border with Asia. The boundary between Europe and Asia is commonly considered to run along the Ural Mountains, Ural River, Caspian Sea, and Black Sea.
Asia is against the eastern border of Europe. The common divider is an imaginary line formed by the Ural Mountains, Ural River, Caspian Sea, Caucasus Mountains, and the Black Sea .
The Ural Mountains, The Ural River, and the Caspian Sea
The Black sea and the Aegean sea
The Ural Mountains that run through Russia and the Ural River, which flows from Russia, through Kazakhstan to the Caspian Sea.
The Caucasus Mountain range forms a natural border between Russia and Southwest Asia. It stretches between the Black Sea and the Caspian Sea, separating Eastern Europe from Western Asia. This range includes notable peaks like Mount Elbrus, which is the highest in Europe. The Caucasus is also significant for its diverse cultures and complex geopolitical landscape.
The Mediterraneasn Sea is to the North of Africa. It seperates Europe from Africa. There are also Middle Eastern counties in Asia which border the Mediterranean.
The Black Sea is most associated with Eastern Europe.
Europe's eastern boundary is formed by the Caspian Sea, Ural River and Ural Mountains. The border also runs through the countries of Russia and Turkey.