The Marmara Region (Turkish: Marmara Bölgesi) is a geographical region of Turkey. Located in northwestern Turkey, it is bordered by Greece and the Aegean Sea to the west, Bulgaria and the Black Sea to the north, the Black Sea Region to the east, the Central Anatolia Region to the southeast and the Aegean Region to the south. At the center of the region is the Sea of Marmara, which gives the region its name. The largest city in the region is Istanbul.