İzmit in the context of "Nicomedia"

The Marmara region (Turkish: Marmara Bölgesi) is a geographical region of Turkey.

Located in East Thrace, it is bordered by Greece and the Aegean Sea to the west, Bulgaria and the Black Sea to the north, the Black Sea Region to the east, and the Aegean Region to the south. At the center of the region is the Sea of Marmara, which gives the region its name. The largest city in the region is Istanbul. Other big cities are Bursa, İzmit, Balıkesir, Tekirdağ, Çanakkale and Edirne.

İznik (Turkish pronunciation: [izˈnik]) is a municipality and district of Bursa Province, Turkey. Its area is 753 km, and its population 44,236 (2022). The town is at the site of the ancient city of Nicaea, from which the modern name derives. The town lies in a fertile basin at the eastern end of Lake İznik, with ranges of hills to the north and south. As the crow flies, the town is only 90 kilometres (56 miles) southeast of Istanbul but by road it is 200 km (124 miles) around the Gulf of İzmit. It is 80 km (50 miles) by road from Bursa.

İznik has been a district centre of the province of Bursa since 1930 but belonged to the district of Kocaeli between 1923 and 1927. It was a township of Yenişehir district (connected to Bilecik before 1926) between 1927 and 1930.

Kocaeli Province (Turkish: Kocaeli ili, pronounced [koˈdʒaeli]) is a province and metropolitan municipality of Turkey and one of only three not to have the same official name as its capital, İzmit, which is thus also sometimes called Kocaeli. Its area is 3,397 km (1,312 sq mi), and its population is 2,102,907 (2023). The province is the successor of the Ottoman-era Sanjak of Kocaeli. The largest towns in the province are İzmit and Gebze. The traffic code is 41.

The province is located at the easternmost end of the Sea of Marmara around the Gulf of İzmit. Kocaeli is bordered by the province of Istanbul and the Marmara Sea to the west, the Black Sea to the north, the province of Sakarya to the east, the province of Bursa to the south and the province of Yalova to the southwest. The metropolitan area of Istanbul extends to the Kocaeli-Istanbul provincial border.

The Hyundai Assan Otomotiv San ve Tic. A.Ş. is an automotive company based in Kozyatagi, Istanbul, Turkey, established at the end of 1994, as a joint venture between the Hyundai Motor Company of South Korea and the Kibar Holding of Turkey. It is operating a manufacturing plant located in İzmit, Turkey that was opened in September 1997, and produces Hyundai automobiles and commercial vehicles.

Yüksek Hızlı Tren or YHT (English: High Speed Train) is a high-speed rail service operated by TCDD Transport in Turkey. Branded as "YHT", they are TCDD Transport's flagship passenger train service and the only high-speed rail service in the country. As of 2025, the network spans 1,385 km (860.6 mi) and serves major cities like Istanbul, Ankara, Eskişehir, İzmit, Konya, and Sivas. Expansion of the system is underway and the network is expected to reach Edirne, Afyonkarahisar, Adana, and İzmir in the 2020s.

High-speed rail in Turkey was originally planned to be built as early as 1975, but it wasn't until 2003 that the construction of the Ankara-Istanbul high-speed railway began. The first section was completed in 2007, between Eskişehir and Esenkent with passenger operations beginning on 13 March 2009 between Eskişehir and Ankara. On 23 August 2011, the Turkish State Railways inaugurated its second high-speed railway to Konya and on 25 July 2014, the railway was opened to Istanbul. The State Railways have integrated the YHT network with other projects done in major urban areas. In Ankara, the route was expanded from three tracks to five tracks to allow for frequent Başkentray commuter rail service, along with a new high-speed rail concourse at Ankara station. In Istanbul, YHT trains use the Marmaray Tunnel to traverse the Bosphorus Strait and reach the European side of the city.

Otoyol 5 (English: Motorway 5), named the Kocaeli Gebze-Bursa-İzmir Motorway (Turkish: Kocaeli Gebze-Bursa-İzmir Otoyolu) and abbreviated as O-5, is a toll motorway in Turkey. Since being completed in 2019, it connects the Istanbul and Kocaeli metropolitan areas with İzmir, via Bursa and Balıkesir. The O-5 runs parallel to the D575 and the D565 for most of its length and is a major motorway in Turkey as it provides a direct connection between Kocaeli and its surrounding metropolis to the country's 3rd largest (İzmir) and 4th largest (Bursa) cities, bypassing the Gulf of İzmit via the Osman Gazi Bridge. The O-5 also makes up part of the International E-road network E881 thus making it one of the most extensive and expensive transport megaprojects.

The western part of the Bursa Beltway, which is part of the O-5, was completed during the 2000s. The rest of the O-5 has been under construction since the early 2010s, with the first portion opened from Altinova to Gemlik in April 2016. As of April 2017, the O-5 is open in two separate sections: the 105.5 km (65.6 mi) section from its northern terminus in Kocaeli, Gebze to Bursa, across the Osman Gazi Bridge along with a 18.2 km (11.3 mi) section from Kemalpaşa to its southern terminus in İzmir. The final section, Karacabey to Akhisar, opened on August 5, 2019.