Zonguldak

i.The Coal Basin and the Pontic Coast

Zonguldak sits on the western Black Sea coast, between Bartın to the east and Düzce to the west, on the narrow coastal strip where the Pontic Alps fall directly into the sea. The provincial seat is built down the steep slopes of a small natural harbour at Zonguldak — itself a 19th-century Republican-era industrial creation, not a pre-modern city. The wider coast, however, has the longest continuous settlement of any of Türkiye's western Pontic coastal districts, anchored by the great Greek colonial city of Heraclea Pontica at modern Karadeniz Ereğli, 35 kilometres east of the central city. The country immediately inland rises sharply to the wooded Pontic ridges; the country southward, beyond those ridges, opens to Bolu and the central plateau.

The defining geological feature of the province is the Zonguldak Coal Basin — the only substantial bituminous coal deposit in Türkiye, running along the coast from Ereğli through Kozlu, Kilimli, and Çaycuma. The coal is hard, low-sulphur bituminous coal of substantial calorific value, suitable for both coking and power generation; it has been the basis of the modern provincial economy since the early 19th century.

ii.Heraclea Pontica — the Megarian Foundation (c. 560 BCE)

The historic-period city of the country was Heraclea Pontica (modern Karadeniz Ereğli), founded about 560 BCE by colonists from the Doric Greek cities of Megara and Tanagra. The new colony was named for the hero Heracles — by tradition the founder of the line of the local Bithynian-Mariandynian kings — and the city's coinage and civic religion remained Heracles-centred through the Hellenistic centuries.

Heraclea grew rapidly into the largest Greek city of the western Black Sea coast. By the 5th century BCE it controlled most of the southern Black Sea littoral from Bithynia to Paphlagonia, with substantial subject Mariandynian villages providing agricultural labour. The city's wealth rested on its protected deep-water harbour, the great Pontic timber trade running inland to the central Anatolian plateau, and the famous Heraclean tuna and bonito fisheries. The standard ancient source is Memnon of Heraclea's History (a fragmentary work of the 1st century BCE, surviving in Photius's medieval excerpts), which is the principal narrative of the city's classical and Hellenistic centuries.

iii.The Mithridatic War and Roman Heraclea

Heraclea passed in succession through Persian Achaemenid satrapal control, brief Athenian and Spartan spheres of influence, and (from the 3rd century BCE) the orbit of the Pontic kingdom. The end of the city's independent existence came in 74 BCE, when Heraclea sided with the Pontic king Mithridates VI Eupator against Rome at the opening of the Third Mithridatic War. The Roman consul Marcus Aurelius Cotta besieged the city for two years — Memnon's account of the siege is one of the most detailed siege narratives in surviving classical literature — before the city's harbour was betrayed in 70 BCE and the city sacked. Cotta carried away the famous bronze statue of Heracles and the city's other portable wealth; the population was substantially reduced by death and enslavement.

Rebuilt by the Romans, Heraclea Pontica continued as a working coastal city of the province of Bithynia-Pontus but never recovered its pre-Mithridatic stature. The Byzantine centuries continued the pattern of slow decline; the famous Cehennemağzı ("Mouth of Hell") cave — the small cave at the foot of the Ereğli citadel that ancient tradition identified as one of the entrances to Hades and as the site of Heracles's twelfth labour (the capture of Cerberus) — has been a Christian pilgrimage site since the Byzantine period.

iv.Byzantine, Genoese, and Ottoman (c. 1360)

Through the Byzantine centuries Heraclea continued as a small coastal city of the Pontic theme. The Genoese commercial expansion of the 13th and 14th centuries established a substantial Genoese trading colony at Heraclea, with a small fortified factory on the harbour; the Genoese remained a significant population well into the Ottoman period. The Ottoman acquisition came around 1360 under the early Ottoman sultans; through the long Ottoman centuries Heraclea (now Ereğli, the Turkish-period contraction of Hēráklēia) was a working coastal town but no longer a major urban centre.

v.The Discovery of Coal (1829)

The transformation of the country into a modern industrial province came with the discovery of coal. The conventional date is 1829, when a Bursalı Mehmet (the name varies in the different historical accounts; the principal version names a man called Uzun Mehmet) noticed black, burnable stone at the small village of Kozlu, a few kilometres east of the modern Zonguldak city. The Ottoman state established the first organised mining operation at Kozlu in 1848; the British military, during the Crimean War (1853–56), made substantial use of Zonguldak coal for the Royal Navy's Black Sea operations, demonstrating the basin's strategic value.

From the 1860s onward the Ottoman state developed the basin systematically. Foreign-led mining companies (principally French, with some German and British participation) opened the deep pits at Kozlu, Kandilli, Çatalağzı, and Üzülmez; a substantial migrant workforce (Türkmen, Lazi, Pomak, and other migrant groups from across the Ottoman empire) was settled in the new mining towns. Under the late Ottoman state the wider mining country was administered under a special Havza-i Fahmiye (Coal Basin) administration. The Ottoman state correspondence still referred to the modern provincial site as "Zonguldak nam mevki" ("the place named Zonguldak") as late as 1896 — reflecting the modern town's late-19th-century origin.

vi.The Republic and the Türkiye Taşkömürü Kurumu

Zonguldak was raised to provincial status under the Republican administrative reorganisation of 1920. The principal Republican investment was the nationalisation of the coal mines in 1940 under the new Ereğli Kömürleri İşletmesi (later the Türkiye Taşkömürü Kurumu, TTK — the Turkish Coal Authority), which took over the operations of the foreign-led companies and consolidated them under state management. Through the 1940s, 50s, and 60s the TTK was one of the largest employers in Türkiye, with over 30,000 workers in the Zonguldak basin at its peak.

The second transformative investment was the opening of the Ereğli Demir ve Çelik Fabrikaları (Erdemir) in 1965 at Karadeniz Ereğli — Türkiye's first integrated iron-and-steel works producing flat-rolled steel products. Erdemir, jointly developed with American technical assistance and partly financed by the Koppers Company (Pittsburgh), used the local Zonguldak coking coal and imported iron ore to produce the steel that supported the country's mid-20th-century industrial expansion. Erdemir was partially privatised in 2006 and remains the principal industrial employer of the province.

vii.The Modern Province

Under the TÜİK 2024 address-based registration count the province population is 586,802. The metropolitan municipality covers eight districts. The largest by population is — unusually for a province — not the central district but the secondary centre Ereğli (~174,000, the Erdemir steel-works town); Merkez (Zonguldak city, ~100,000) is the administrative capital; Çaycuma (~83,000) and Devrek (~52,000) inland; Alaplı, Gökçebey, Kilimli, and Kozlu complete the province. The province has seen the gradual contraction of the coal-mining workforce since the 1990s, balanced by the continuing operation of Erdemir, the small-but-steady fishing industry, and the developing rural-and-mountain tourism in the western districts.

The province is the seat of Zonguldak Bülent Ecevit Üniversitesi (founded 1992, renamed in 2012 after the Zonguldak-born former prime minister Bülent Ecevit, 1925–2006). The 1992 Kozlu mine disaster (3 March 1992; 263 miners killed in a methane explosion at the Karadon mine in Kozlu) remains the worst industrial accident in modern Turkish history; a small memorial in Kozlu commemorates the dead.

viii.What to See, in Order

The walking shape of Zonguldak city is the shape of a 20th-century industrial town: harbour, miners' housing along the slopes, the Republican-period Türkiye Taşkömürü Kurumu Genel Müdürlüğü headquarters, and the small Maden Müzesi ("Mining Museum") at the harbour, with the principal collection of mining tools and Zonguldak's industrial history. The atmospheric small Üzülmez Galerisi (the former mining gallery converted to a visitable museum) gives a sense of the underground world that built the city.

The principal historical site of the province is Karadeniz Ereğli, 35 kilometres east. The route runs through the modern industrial city to the small Heraclea Pontica archaeological park on the harbour headland (with the surviving Byzantine-period walls, the small archaeological museum, and the ruined Genoese tower), and to the Cehennemağzı Mağaraları ("Mouth of Hell Caves") — the three connected caves on the western edge of Ereğli town, identified by ancient tradition as Heracles's entrance to Hades and used as a Christian pilgrimage chapel through the Byzantine and Genoese periods. The wider Zonguldak coast offers the small beach resorts of Alaplı and Filyos (with the archaeological site of ancient Tieion, a small Greek colonial town).

The western Pontic coal coast — Megarian Heraclea of Heracles' twelfth labour, the Genoese tower above the harbour, the deep pits of Kozlu, and the steel that built modern Türkiye.

For the parallel western Black Sea provinces, see Kastamonu to the east and Bolu to the south. For Türkiye's Black Sea coast and industrial geography in the wider sense, visit our sister site CountryOfTurkey.com.