The nation on the Caspian Sea is IRAN, which is a country located in the Middle East. It is bordered by Iraq, Turkey, Armenia, Azerbaijan, Turkmenistan, and Afghanistan. IRAN has a long history, dating back to the Achaemenid Empire in 550 BC. It is the second-largest nation in the Middle East and the 18th-largest in the world. IRAN is a major regional power and has significant influence in international affairs.