Azerbaijan, country of eastern Transcaucasia. Occupying an area that fringes the southern flanks of the Caucasus Mountains, it is bounded on the north by Russia, on the east by the Caspian Sea, on the south by Iran, on the west by Armenia, and on the northwest by Georgia. The exclave of Naxçıvan (Nakhichevan) is located southwest of Azerbaijan proper, bounded by Armenia, Iran, and Turkey. Azerbaijan includes within its borders the region of Nagorno-Karabakh, which until 2023 had a predominantly Armenian population and from 1988 has been the focus of intense conflict between Azerbaijan and Armenia. The capital of Azerbaijan is the ancient city of Baku (Bakı), whose harbor is the best on the Caspian Sea.