Kocaeli located in the section of Çatalca-Kocaeli in Marmara regionbetween n East longitude 29°22'-30°21' and North latitude 40° 31'- 41°13'. There is Sakarya province in East and Southeast, Bursa province in South, Yalova province, the Gulf of ‹zmit, Marmara Sea and Istanbul province in West and Blacksea in North. . East longitude of 30° is considered essential for Turkish local time. The surface area of Kocaeli is 3.505 km2. It is located over an important road junction United Asia with Europe.The Gulf of ‹zmit, which is a natural port, is a busy seaway. ‹stanbul Provincial border on the northwest passes through the East of Kemiklidere flowing between Gebze and ‹stanbul. ‹stanbul-Kocaeli border in Southwest ends on the lands of Yalova across the Gulf of ‹zmit. The line passes through the hills of Samanl› Mountain forms Bursa border. The border reaches Sakarya Province in the shores of Sapanca Lake near Maflukiye.
Samanl› Mountains begin to rise from the West bank of Sakarya River and extends until Bozburun in the North of Pamukovaand ‹znik Lake. It has an overlooking position over ‹zmit, Sapanca and Adapazar› depression fields. The summit of the Samanl› Mountains is Kartepe (previous Keltepe) in 1,601 m height. The other important mountains in the province are Dikmen Mountain (1.387 m), Naldöken Mountain (1.125 m), Naz Mountain (917 m)and Çene Mountain (646 m).
b) Plains and Plateaus
There are many small brook valleys in the province. Plains are generally in quality of small alluvial level areas formed by the drifts of streams. The valleys which were formed by the streams flowing into Blacksea appeared before the tectonic movements that caused reshaping of Kocaeli Peninsula. On the other hand, stream valleys flowing into the Marmara Sea appeared after the tectonic movements.
A part of the streams rising in the land of province reach to Karadeniz, the other part reaches to Marmara Sea. Theridges of the mountains extending in the Kocaeli Peninsula are nearer to the Gulf of ‹zmit and Marmar; therefore the streams flowing into Blacksea are longer. Riva (Çaya€z›) brook that rises from the Tepecik village in Gebze is 71 km in long and flows into Karadeniz in the East of Bosphorous. Kocadere is 50 km in long. Kirazdere that rises from Samanl› Mountains flows into the Gulf in ‹zmit.
The surface area of Sapanca Lake is 47 km2. It is surrounded by Uzuntarla, Maflukiye and Eflma towns. The artificial lake that is located behind the Kirazdere Dam lays over a land of 1,74 km2 Yuvac›k Dam Reservoir was constructed by the Metropolitan Municipality in order to meet the need of water for people.
Climate is mild in the shores of Gulf, harsh in the mountinous sections. Hot and less rainy in summer in the center of province and rainy, sometime snowyin winters. The highest temperature measured is 41,6°C (11 August 1970. Climate in the hillsides Samanl› Mountains open to the Gulf resembles that of Karadeniz shores.
Flora in Kocaeli generally has characteristics of Marmara Region. However there is difference between shores The spacesbetwen the Samanl› Mountains and Karadeniz shores is covered with thick and hygrophilous forests. Maquis specific to Mediterrenian climate is seen in the North and Morthesasy of the Gulf of ‹zmit.
İzmit Sekapark: In Sekapark, which is actualized as a first industrial transformation area, is a coastal complex which could be used for having a rest and doing sport. There are a huge artificial grass hill 15 m high and 150 m size, the biggest skateboard in our country, artificial sand beach, multi functional landing stages, a platform of concert and perform for over one thousand people , hundred thousands m2 grass area, 6 thousand trees, 23 km pedestrian lane, 1600 m bike lane and a car park with 800 cars capacity. There are also cafes, meat and fish restaurants and a grass field. In this beautiful area you can have a rest, do sport and eat something with your friends as well as you can get on the net with the connection of Kocaeli Metropolitan Municipality.