Kocaeli Province in the context of "Gulf of İzmit"

Bursa Province (Turkish: Bursa ili) is a province and metropolitan municipality in Turkey along the Sea of Marmara coast in northwestern Anatolia. It borders Balıkesir to the west, Kütahya to the south, Bilecik and Sakarya to the east, Kocaeli to the northeast and Yalova to the north. Its area is 10,813 km, and its population is 3,194,720 (2022). Its traffic code is 16.

Almost all of Bursa Province (including the city of Bursa) is in the Marmara region, but the districts of Büyükorhan, Harmancık, Keles and Orhaneli are in the Aegean Region.

Bilecik Province (Turkish: Bilecik ili) is a province in midwest Turkey, neighboring Bursa to the west, Kocaeli and Sakarya to the north, Bolu to the east, Eskişehir to the southeast and Kütahya to the south. Its area is 4,179 km, and its population is 228,673 (2022). Most of the province laid down in Marmara region but eastern parts of Gölpazarı and Söğüt district and districts of İnhisar and Yenipazar remained in Black Sea Region, smaller southeastern parts of Bozüyük and Söğüt remained in Central Anatolia Region and smaller southwestern part of Bozüyük remained in Aegean Region.

İzmit (Turkish pronunciation: [ˈizmit]) is a municipality and the capital district of Kocaeli Province, Turkey. Its area is 480 km, 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 100 km (62 mi) 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 İzmit is coterminous with its province. It is also the most populated of any city or town in Turkey whose name isn't shared with the province it is located in.

İzmit was known as Nicomedia and Ólbia in antiquity, and was the eastern and most senior capital city of the Roman Empire between 286 and 324, during the Tetrarchy introduced by Diocletian. Following Constantine the Great's victory over co-emperor Licinius at the Battle of Chrysopolis in 324, Nicomedia served as an interim capital city for Constantine between 324 and 330. During the Ottoman Empire, İzmit was the capital of the Sanjak of Kocaeli. In the present day, Istanbul-İzmit area is one of the main industrial regions in Turkey.

Sakarya (Turkish: Sakarya ili) is a province and metropolitan municipality in Turkey, located on the coast of the Black Sea. Its area is 4,824 km (1,863 sq mi), and its population is 1,110,735 (2024). The Sakarya River creates a webbing of estuaries in the province, which is in the Marmara Region. The adjacent provinces are Kocaeli to the west, Bilecik to the south, Bolu to the southeast and Düzce to the east. The capital of Sakarya is Adapazarı. Its climate is maritime in the north and humid subtropical in the south and changes by the distance to the Black Sea.Sakarya is on the Ankara-Istanbul highway and is also connected by rail. Sakarya is serviced by Istanbul's Sabiha Gökçen International Airport. The mayor of Sakarya is Yusuf Alemdar as of 2024 (AKP). The city of Sakarya, one of the most important cities in Turkey for its rapid growth and development, is known for its natural surroundings and culture. Home to several resort towns, Sakarya has access to the sea, beaches, lakes, rivers, highlands, thermal springs, traditional Ottoman lifestyle districts such as Taraklı and Geyve and noteworthy historical relics from the Byzantine and the Ottoman eras.The Turks conquered the city of Sakarya in the 13th century. There was intensive immigration from the Caucasus and the Balkans in the 18th and the 19th centuries. The last massive immigration was in 1989 from Bulgaria. The pronvince's location at a transportation crossroads has made spurred development in the manufacturing sector, and it still has inward migration from other parts of Turkey.

Yalova Province (Turkish: Yalova ili) is a province in northwestern Turkey, on the eastern coast of the Sea of Marmara. Its adjacent provinces are Bursa to the south and Kocaeli to the east. Its area is 798 km (making it the smallest province of Turkey), and its population is 296,333 (2022). Prior to 1930, the area around Yalova constituted a district of Kocaeli Province; from 1930 to 1995, it was part of Istanbul Province; in 1995, the area was separated and made into the current Yalova Province. The provincial capital is the city of Yalova.

Ford Otomotiv Sanayi A.Ş. (Turkish for 'Ford Automotive Industry'), doing business as Ford Otosan, is an automotive manufacturing company based in Turkey that is equally owned by Ford Motor Company and Koç Holding. The company was established in its current form in 1977, with original relations dating back to 1928. It currently operates in six locations: Gölcük and Yeniköy plants in Kocaeli, İnönü plant in Eskişehir, Craiova plant in Romania, Sancaktepe R&D Center and spare parts warehouse in Istanbul. The company employs more than 20,000 people and had a production capacity of over 934,500 vehicles, 430,000 engines, and 112,000 powertrains by 2024.

Karamürsel is a municipality and district of Kocaeli Province, Turkey. Its area is 262 km, 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.

Karamürsel holds special significance for the Turkish Navy, as it was here in 1323 that the Ottoman Empire first established an outlet to the sea, thus laying the foundations for the Ottoman Navy which would go on to dominate the eastern Mediterranean for several centuries.

Kartepe is a municipality and district of Kocaeli Province, Turkey. Its area is 301 km, and its population is 136,625 (2022). The mayor is Mustafa Kocaman (AKP).