A narrow and busy waterway with a complex legal status
The Turkish Straits consist of two narrow straits in northwestern Turkey, the Bosporus and the Dardanelles, and the Sea of Marmara that connects them. The Turkish Straits lie between the Black Sea to the east and the Aegean Sea, which is a region of the much larger Mediterranean Sea. Traditionally, the Turkish Straits are considered a boundary between Europe (to the north and west) and Asia (to the south and east). The Turkish Straits are an international waterway, governed by the Montreux Convention Regarding the Regime of the Straits, 1936. Connecting to the Black Sea, the Bosporus is about 19 miles in length and, at its narrowest, less than one-half mile wide. A portion of the Bosporus runs through the heart of Istanbul, where it is crossed by two bridges. The Dardanelles opens into the Aegean. In ancient times, it was referred to as the Hellespont. The Gallipoli Peninsula on the north shore of the Dardanelles was the site of a major campaign during World War I. Under the Montreux Convention, Turkey exercises sovereign rights over the Turkish Straits, but with some restrictions relating to passage of ships. Merchant vessels of all nations have freedom of transit during times of peace. Passage of non-Turkish military vessels is restricted. Generally, those military vessels may not exceed 15,000 tons. No more than nine warships of nations not bordering the Black Sea, with a total aggregate tonnage of not more than 30,000 tons are permitted to transit the Straits at any one time and such a warship may not stay in the Black Sea for more than three weeks. No aircraft carriers are permitted to transit the Turkish Straits. On several occasions, the Soviet Union/Russia has sent a “large aircraft carrying cruiser” through the Straits. The Western Powers lodge protests when this occurs. With the increase in the numbers and size of vessels transiting the Straits, the Government of Turkey has sought to impose traffic measures to enhance safety and environmental protection. These measures are mostly recommendatory but are generally followed by transiting vessels.