Sakarya is a province of Turkey and is located in the Marmara region. Its adjacent provinces are Kocaeli to the west, Bilecik to the south, Bolu to the southeast, and Duzce to the east. In the year 2000, its population was approximately 750,000. The capital of Sakarya is Adapazari.
The province land is surrounded by Duzce and mountain of Bolu from the East; by Golpazari and Osmaneli districts of Bilecik from the South; by Kandira, Izmit, and Golcuk districts of Kocaeli from the West, and by the Black Sea from the North in the term of administratition.
It is poured to the river of Sakarya from the village of Seyfiler in the north-east of the district.
The weather in the province is rainy and humid, and the climate is mild.
Erdek to the northwest of Bandirma is known for its beaches and the historical structures at Kyzikos.
The Aegean shores of Balikesir Province borders the Edremit Bay.
The Sakarya River flows through the center of the lands of BilecikProvince, which is a rather important province from the point of view of Ottoman history.