It has an area of 5,196 km² and a population of 12,573,836 (2007 est). The population was 10,018,735 in 2000. It is surrounded by the provinces of TekirdaÄŸ to the west, Kocaeli to the east, the Black Sea to the north and the Sea of Marmara to the south. The Bosphorus (BoÄŸaziçi) Strait divides the province in two parts: the European side and the Asian side. The capital of the province is the city of Istanbul which covers much of the province.