Populated places in Kocaeli Province

İzmit () is a municipality and the capital district of Kocaeli Province, Turkey. Its area is 480 km2, and its population is 376,056 (2022). The capital of Kocaeli Province, it is located at the Gulf of İzmit in the Sea of Marmara, about east of Istanbul, on the northwestern part of Anatolia. Kocaeli Province (including rural areas) had a population of 2,079,072 inhabitants in 2022, of whom approximately 1.2 million lived in the largely urban İzmit City metro area made up of Kartepe, Başiskele, Körfez, Gölcük, Derince and Sapanca (in Sakarya Province). Similar to Istanbul, the area of İzmi

Gebze () is a working-class district and one of the municipalities in Kocaeli Province, Turkey. Its area is 418 km2, and its population is 407,019 (2022). It is situated 65 km (30 mi) southeast of Istanbul, on the Gulf of Izmit, the eastern arm of the Sea of Marmara. Gebze is the largest district by population size in the province as of 2022, exceeding İzmit, the provincial capital. Its population consists of a colossal working class, one of the largest in Turkey, as it hosts 10 industrial parks, in which hosts 1,384 companies and over 130,000 people are employed.

town of Kocaeli Province in Turkey

thumb|Kaymakam Mahmut Kılıçdoğan Footbridge crossing over state road State road D.100 (Turkey)|D.100 in Derince. Derince is a seaport, municipality and district of Kocaeli Province, Turkey. Its area is 198 km2, and its population is 146,374 (2022). The mayor is Sertif Gökçe (CHP).

Körfez, formerly known as Elaia, or Elaea, is a municipality and district of Kocaeli Province, Turkey. Its area is 301 km2, and its population is 178,048 (2022).

Karamürsel is a municipality and district of Kocaeli Province, Turkey. Its area is 262 km2, and its population is 59,676 (2022). It is on the south coast of the Gulf of İzmit. Before its conquest by the Ottomans it used to be called by the Greek name of Praenetos (Πραινετός in Greek). The modern name commemorates Kara Mürsel who founded the Ottoman navy and designed distinctive galley ships, called kadırgas, for it.

thumb|Kerpe beach thumb|right|A beach in Cebeci village, Kefken Island|Kefken, Kandıra. Kandıra is a municipality and district of Kocaeli Province, Turkey. Its area is 840 km2, and its population is 52,874 (2022). Its neighbours are Kaynarca to the east, Adapazarı to the southeast, İzmit to the south and Şile to the west.

Dilovası is a municipality and district of Kocaeli Province, Turkey. Its area is 125 km2, and its population is 53,416 (2022). The district Dilovası was created in 2008 from part of the district of Gebze, along with the districts Darıca and Çayırova. The mayor is Hamza Şayir (AKP).

250px|thumb|right|Kartepe Historical Wisdom Mosque Kartepe is a municipality and district of Kocaeli Province, Turkey. Its area is 301 km2, and its population is 136,625 (2022). The mayor is Mustafa Kocaman (AKP).

ilçe (district), administrative county of Kocaeli, northwestern Turkey

Başiskele, formerly known as Astacus, is a municipality and district of Kocaeli Province, Turkey. Its area is 23 km2, and its population is 116,650 (2022). The mayor is Hüseyin Ayaz (AK Party).

Elbizli is a village (officially a neighborhood) in Gebze District, Kocaeli Province, Turkey. Its population is 151 (2023).