Sakarya (Turkish: Sakarya ili) is a province in Turkey, located on the coast of Black Sea. The Sakarya River creates a webbing of estuaries in the province. Sakarya is located in the Marmara Region. Its adjacent provinces are Kocaeli to the west, Bilecik to the south, Bolu to the southeast, and Düzce to the east. The capital of Sakarya is Adapazarı. The climate is oceanic due to its close proximity to the Black Sea.Sakarya is situated on the Ankara-Istanbul Highway.