The Kocaeli Peninsula ( tr, Kocaeli Yarımadası) lies in the northwest corner of

Anatolia Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The re ...

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

, separating the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

and the

Sea of Marmara The Sea of Marmara,; grc, Προποντίς, Προποντίδα, Propontís, Propontída also known as the Marmara Sea, is an inland sea located entirely within the borders of Turkey. It connects the Black Sea to the Aegean Sea via the ...

on the Asian side of the strait of

Bosphorus The Bosporus Strait (; grc, Βόσπορος ; tr, İstanbul Boğazı 'Istanbul strait', colloquially ''Boğaz'') or Bosphorus Strait is a natural strait and an internationally significant waterway located in Istanbul in northwestern Tu ...

. Approximately one-third of

Istanbul Istanbul ( , ; tr, İstanbul ), formerly known as Constantinople ( grc-gre, Κωνσταντινούπολις; la, Constantinopolis), is the List of largest cities and towns in Turkey, largest city in Turkey, serving as the country's economic, ...

, one of the most populous cities of the world, occupies its western part, and

İzmit İzmit () is a district and the central district of Kocaeli province, Turkey. It is located at the Gulf of İzmit in the Sea of Marmara, about east of Istanbul, on the northwestern part of Anatolia. As of the last 31/12/2019 estimation, the c ...

, another big city, is at the easternmost point of the peninsula.

Geography

The peninsula is at the north west corner of

. The length toward west is and the average width is about . It is bordered by the

to the north,

to the south and the strait of

( tr, Boğaziçi) to the west. The geographers consider it to be a part of Kocaeli Çatalca subregion, where

Çatalca Çatalca (Metrae; ) is a city and a rural district in Istanbul, Turkey. It is the largest district in Istanbul by area. It is in East Thrace, on the ridge between the Marmara and the Black Sea. Most people living in Çatalca are either farmers or ...

is a peninsula on the other side of Bosphorous.

History

Together with the strait of

Dardanelles The Dardanelles (; tr, Çanakkale Boğazı, lit=Strait of Çanakkale, el, Δαρδανέλλια, translit=Dardanéllia), also known as the Strait of Gallipoli from the Gallipoli peninsula or from Classical Antiquity as the Hellespont (; ...

, the passage through Bosphorus and the Kocaeli peninsula is the main passage of people from

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. During ancient times,

Phrygia In classical antiquity, Phrygia ( ; grc, Φρυγία, ''Phrygía'' ) was a kingdom in the west central part of Anatolia, in what is now Asian Turkey, centered on the Sangarios River. After its conquest, it became a region of the great empires ...

ns,

Bithynia Bithynia (; Koine Greek: , ''Bithynía'') was an ancient region, kingdom and Roman province in the northwest of Asia Minor (present-day Turkey), adjoining the Sea of Marmara, the Bosporus, and the Black Sea. It bordered Mysia to the southwest, Pa ...

ns and

Galatians Galatians may refer to: * Galatians (people) * Epistle to the Galatians, a book of the New Testament * English translation of the Greek ''Galatai'' or Latin ''Galatae'', ''Galli,'' or ''Gallograeci'' to refer to either the Galatians or the Gauls in ...

were some of them. But while Phrygians and Galatians moved to

Central Anatolia The Central Anatolia Region ( tr, İç Anadolu Bölgesi) is a geographical region of Turkey. The largest city in the region is Ankara. Other big cities are Konya, Kayseri, Eskişehir, Sivas, and Aksaray. Located in Central Turkey, it is bordered ...

, it was the Bithynians who controlled the region for a considerable time.

Hannibal Hannibal (; xpu, 𐤇𐤍𐤁𐤏𐤋, ''Ḥannibaʿl''; 247 – between 183 and 181 BC) was a Carthaginian general and statesman who commanded the forces of Carthage in their battle against the Roman Republic during the Second Puni ...

, the

Carthaginian The term Carthaginian ( la, Carthaginiensis ) usually refers to a citizen of Ancient Carthage. It can also refer to: * Carthaginian (ship), a three-masted schooner built in 1921 * Insurgent privateers; nineteenth-century South American privateers, ...

commander who took refuge in Bithynia, died in Kocaeli Peninsula at around 182 BC. His grave may be around

Dilovası Dilovası is a town and district of Kocaeli Province in the Marmara region of Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on t ...

or at

Gebze Gebze (,) is a district in Kocaeli Province, Turkey. 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 per population size in the province as o ...

both at about the middle of Kocaeli Peninsula. Later the peninsula was a part of the

Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...

, the

Byzantine Empire The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...

, and the

Ottoman Empire The Ottoman Empire, * ; is an archaic version. The definite article forms and were synonymous * and el, Оθωμανική Αυτοκρατορία, Othōmanikē Avtokratoria, label=none * info page on book at Martin Luther University) ...

. In Byzantine times and among the local Greek population until the early 20th century, the peninsula was known as Mesothynia (Μεσοθυνία, "Middle

Thynia In the ancient world, Thynia (, el, Θυνία) was a region of Europe along the northern coast of the Propontis, opposite Bithynia on the Asian side.W.H.Race, ''Apollonius Rhodius: Argonautica'', Loeb Classical Library (2008), introductory maps ...

").

Population and economy

Kocaeli Peninsula is one of the most industrialised regions of Turkey. Approximately one-third of

, one of the most populous cities of the world, lies on the westernmost point of the Kocaeli peninsula, and

, another big city, is at the easternmost point of the peninsula. The southern coastline (Marmara) between the two is dotted with settlements, factories and the shipyards. Population density along this coastline is very high, as opposed to the northern (Black Sea) coastline.Geography portal
/ref>

References

{{coord, 41, 00, N, 29, 36, E, type:landmark_source:kolossus-frwiki, display=title Marmara Region Peninsulas of Turkey Landforms of Istanbul Province Landforms of Kocaeli Province