The Bay of Kotor (Montenegrin and Serbian: Boka kotorska/Бока которска, pronounced [bɔ̂ka kɔ̂tɔrskaː]), known simply as Boka, is a winding bay of the Adriatic Sea in southwestern Montenegro. The bay, once called Europe’s southernmost fjord, is in fact a ria of the disintegrated Bokelj River which used to run from the high mountain plateaus of Orjen.
The bay is about 28 km long from the open sea to the harbor of the city of Kotor. It is surrounded by mountains of Orjen on the west and Lovćen on the east. The narrowest section, Verige strait, is only 300 m long. It has a shoreline of 107.3 km. As of 2013, it can be crossed by a ferryboat, but Montenegro is planning to build a bridge to span the strait, the so-called Verige Bridge.
The bay has been inhabited since antiquity. Its well preserved medieval towns of Kotor, Risan, Tivat, Perast, Prčanj and Herceg Novi, along with their natural surroundings, are major tourist attractions. Natural and Culturo-Historical Region of Kotor has been a World Heritage Site since 1979.