Kartepe, the highest mountain in the vicinity of Kocaeli and Sapanca is located between the altitudes of 1150 meters and 1640 meters in the southeast of Kocaeli. The hill, at 125 km. distance to Istanbul, dominates Sapanca Lake and Izmit Bay. Although still not much known, the Sapanca Lake and its surroundings have always visitors. If you are living in Istanbul or Kocaeli and their peripheries and still not see, we advise you to come for a visit as soon as possible.