Zonguldak is a province along the western Black Sea coast region of Turkey. The province is 3,481 km2 in size and has a population of 615,599. Its adjacent provinces are Duzce to the southwest, Bolu to the south, Karabuk to the southeast, and Bartın to the east. The capital is Zonguldak. Since the discovery of coal in the province, Zonguldak has become a major coal production center.