Gebze (Turkish pronunciation: [ˈɟebze], ancient names: Dakibyza and Libyssa, Λίβυσσα in Ancient greek) is a district in Kocaeli Province, Turkey. It is situated 30 miles east of Istanbul, on the northern shore of the Sea of Marmara. Gebze is the second largest district in Kocaeli after İzmit, the provincial centrum in terms of population.