Brunca (Bithynia)

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). The mayor is Şener Söğüt (AKP) and the district governor is Uğur Kalkar, appointed in August 2022. The cement plant is a major source of greenhouse gas.

Gulf of İzmit (Turkish: İzmit Körfezi), also referred to as Izmit Bay, is a bay at the easternmost edge of the Sea of Marmara, in Kocaeli Province, Turkey. The gulf takes its name from the city of İzmit. Other cities and towns around the bay are Gebze, Körfez, Gölcük, and Altınova. In the east–west direction, it extends for a length of about 48 kilometres (30 mi), while in the north–south direction its width varies from 2 to 3 kilometres (1.2 to 1.9 mi) at the narrowest spots to about 10 kilometres (6.2 mi) at its widest. The İzmit Bay Bridge is a suspension bridge that bridges the gulf. The North Anatolian Fault Zone, the most prominent active fault in Turkey and the source of numerous large earthquakes throughout history, passes through the Gulf of İzmit.

Tüpraş Izmit Oil Refinery (Turkish: Tüpraş İzmit Rafinerisi) is an oil refinery in Izmit, western Turkey. It is owned and operated by Tüpraş. Amongst others it refines Urals crude. Its capacity is slightly less than that of Tüpraş Izmir. It produces diesel fuel. Climate Trace estimates that in 2023 it emitted almost 3 million tonnes of greenhouse gas.

Hereke is a settlement in Kocaeli province, Turkey, located to the north of the Gulf of İzmit, near Istanbul. It is famous for Hereke carpets. It was bound to Gebze district until transferring to Körfez in 1987. It was an independent municipality until it was merged into the municipality of Körfez in 2008. It consists of 17 Ağustos (August 17), Agah Ateş, Cumhuriyet, Hacı Akif, Kışladüzü (formerly village), Şirinyalı (formerly village) and Yukarı Hereke mahalles. It can be reached by minibus (from Gebze and İzmit), public bus (from Darıca, Gebze and İzmit), Adapazarı Express train, ship and sea bus.

Charax in Bithynia (Ancient Greek: Χάραξ της Βιθυνίας or Χάρακας της Βιθυνίας) was a Roman and Byzantine port town of ancient Bithynia, in what is now Turkey. It was on the north side of the Sinus Astacenus on the road between the erstwhile Eastern Roman and Byzantine capital Nicomedia and Libyssa. Stephanus of Byzantium calls it a place of great trade.Its site is located near Hereke, in Asiatic Turkey.

Elaea or Elaia (Ancient Greek: Ελαία) was a town of ancient Bithynia on the coast of the Sinus Astacenus in the Propontis. Its site is located near Zeytin Burnu (Körfez), in Asiatic Turkey.

İzmit Körfez Circuit (Turkish: İzmit Körfez Yarış Pisti) is a motor sports race track about 17 km (11 mi) west of İzmit, in Körfez district of Kocaeli Province, Turkey. Sponsored by the Turkish Automobile Sports Federation (TOSFED) and built by the Istanbul Motorsports Club (İMK), it was inaugurated in 1993 as the first asphalted race track in Turkey. The venue is home to motor sport races in various categories. Located at the northeastern coast of Marmara Sea, İzmit Körfez Circuit is situated around a small Fener Lake (Fenergölü), which belongs to the Municipality of Körfez District. The venue can be easily reached from Istanbul and İzmit by the motorway O-4 or highway D-100 at the exit Körfez. The race track, 1.950 km (1.212 mi) at length, has nine turns and runs clockwise. The circuit provides the greatest number of motor sport racing events in Turkey. In addition to Turkish championships, several racing organizations of private companies as well as various motor sport types in different categories are held here. On an average racing day, several events are carried out in five to six categories. The circuit is used also for test runs by motor magazines, tire and motor companies. Some motorcycle and auto racing schools train here also. Around 5,000 spectators in every age group come to the circuit on racing days. Events at the race track find growing interest in the TV and press.

The Hereke Tunnel (Turkish: Hereke Tüneli), is a motorway tunnel constructed on the Istanbul–Ankara motorway O-4 E80 in Kocaeli Province, northwestern Turkey. It was opened to traffic in 1984. It is situated in Körfez district of Kocaeli Province. The 281–285-metre (922–935 ft) long twin-tube tunnel carries three lanes of traffic in each direction. The tunnel was constructed in the 1980s. During the 1999 İzmit earthquake, the tunnel was light damaged. In 2012, the tunnel's both tubes were reinforced. In the time period of 2013–2014, the tunnel was modernized for traffic safety. Around 55,000 vehicles pass through the tunnel in both directions daily.

Değirmendere Merkez is a neighbourhood in the municipality and district of Gölcük, Kocaeli Province, Turkey. Its population is 6,226 (2022). Değirmendere was an independent municipality until it was merged into the municipality of Gölcük in 2008. The town is located on the south coast of Izmit Bay, between Gölcük and Halidere. It was the epicenter of the 1999 Marmara earthquake that almost wiped out the town as well as neighboring towns. Değirmendere is well known for its hazelnuts, sweet cherries, and public cultural activities.

Gölcük Naval Base (Turkish: Gölcük Deniz Ana Üssü) is the main base of the Turkish Navy on the east coast of the Sea of Marmara in Gölcük, Kocaeli. It is the principal base for logistic support with various facilities stretched over 1,800 acres (7.3 km2) of land. In addition to the workplaces, the base houses apartment-like barracks, social facilities, a military hospital, a military museum and an archive for naval history. The shipyard at the base is capable of constructing frigates, submarines, fast attack boats and auxiliary vessels with high technology in recognized standards.

Gölcük Naval Shipyard (Turkish: Gölcük Donanma Tersanesi) is a naval shipyard of the Turkish Navy within the Gölcük Naval Base on the east coast of the Sea of Marmara in Gölcük, Kocaeli. Established in 1926, the shipyard serves for the building and the maintenance of military vessels. A total of 3,221 personnel are employed at the shipyard stretching over an area of 255,526 m2 (2,750,460 sq ft) with covered structures of 121,466 m2 (1,307,450 sq ft).

Praenetus or Prainetos (Ancient Greek: Πραίνετος), also known as Prinetos or Prinetus (Πρίνετος) was a town of ancient Bithynia on the coast of the Propontis. It on the north side of Mount Arganthonius (Samanli Daği), and at the southern entrance of the Sinus Astacenus. It was situated 28 Roman miles to the northwest of Nicaea. Stephanus of Byzantium calls it Pronectus or Pronektos (Πρόνεκτος) and states that it was founded by the Phoenicians. If this be true, it would be a very ancient place, which can scarcely be conceived, as it is mentioned only by very late writers. According to Cedrenus it was destroyed by an earthquake. It was a bishopric; no longer the seat of a residential bishop, it remains a titular see of the Roman Catholic Church.Its site is located near Karamürsel, in Asiatic Turkey.