Gebze is a district and municipality located in the Kocaeli Province of Turkey. Formerly known as Libyssa, it covers an area of 418 km2 and is situated approximately 65 km southeast of Istanbul on the Gulf of Izmit, which serves as the eastern arm of the Sea of Marmara.
As of 2022, Gebze is the largest district in Kocaeli Province by population, with a total of 407,019 residents. The area is characterized by a large working-class population, driven by its status as an industrial hub. It hosts 10 industrial parks that employ over 130,000 people across 1,384 different companies.