Bilecik Province is a province in midwest Turkey, neighboring Bursa to the west, Kocaeli and Sakarya to the north, Bolu to the east, Eskisehir to the southeast and Kütahya to the south, spanning an area of 4,307 km². Population is 225,381. Most of the province laid down in Marmara Region but eastern parts of Gölpazari and Sögüt district and districts of Inhisar and Yenipazar remained in Black Sea Region, smaller southeastern parts of Bozüyük and Sögüt remained in Central Anatolian Region and smaller southwestern part of Bozüyük remained in Aegean Region.