Kartepe, then known as Köseköy, was founded in 1600s. After the Population exchange between Greece and Turkey agreement, Turks from Greece were settled in Köseköy in 1920s. Later people from Black Sea coast were also settled around Köseköy. Being a part of industrial area the population increased and in 1970 it was declared a seat of township. In 2008 it was merged to nearby towns, renamed as Kartepe and became a district center of Kocaeli Province. The municipality of Kartepe is now an intracity municipality of Greater Kocaeli.
Industrial estates around Kartepe constitute the major revenue of the city. Another important sector is mountain tourism. Although Kartepe is founded in the low plains the mountains at the south serve as winter sports complex for nearby İstanbul citizens.
The rural area of the district
There are 10 villages in the rural area of the district. The total population (urban+rural) of the district is 93,809.