Paphlagonia was an ancient area on the northern central Black Sea coast of Anatolia, situated between Bithynia and Pontus, separated from Galatia by a prolongation to the east of the Bithynian Olympus. According to Strabo, the river Parthenius fromed the western limit of the region, which was bounded on the east by the Halys river.

Although the Pahplagonians play scarcely any part in history, they were one of the most ancient nations of Anatolia (_Iliad_, ii. 85). They were mentioned by Herodotus among the peoples conquered by Croesus and they sent an important contingent to the army of Xerxes in 480 BCE. Xenophon speaks of them as being governed by a prince of their own, without any reference to the neighboring satraps, a freedom perhaps due to the nature of their country, with its lofty mountain ranges and difficult passes. At a later period, Paphlagonia passed under the control of the Macedonian kings and, after the death of Alexander the Great, it was assigned, together with Cappadocia and Mysia to Eumenes. However, it continued to be governed by native princes until it was absorbed by the encroaching power of Pontus. The rulers of that dynasty became masters of the greater part of Paphlagonia as early as the reign of Mithradates III (302-266 BCE), but it was not until the reign of Pharnaces I that the city of Sinope fell under their control. From that time, the whole province was incorporated into the kingdom of Pontus untill the fall of Mithradates VI (65 BCE). Pompey united the coastal districts of Paphlagonia with the Roman province of Bithynia, but left the interior of the country under the native princes until the dynasty became extinct and the whole country was incorporated into the Roman Empire. All these rulers appear to have borne the name Pylaimenes as a token of that they claimed descent from the chieftain of that name who figures in the Iliad as leader of the Paphlagonians. Under the Roman Empire, Paphlagonia, along with the greater part of Pontus, was united into one province with Bithynia, as we find to have been the case with Pliny the Younger; but the name was still retained by geographers, though its boundaries are not distinctly defined by Claudius Ptolemy. Paphlagonia reappears as a separate province in the 5th century CE (Hierocles, _Synecd._ c. 33)

In the times of the Hittites, it was inhabited by the Kashka people. The exact ethnic relations of the Paphlagonians are uncertain. It seems perhaps that they were related to the people of the adjoining country, Cappadocia, who were of the Anatolian branch of the Indo-Europeans. Their language would appear from Strabo's testimony to have been distinctive.

The greater part of Paphlagonia is a rugged mountainous country, but it contains fertile valleys and produces great abundance of hazelnuts and fruit, particularly plums, cherries and pears. The mountains are clothed with dense forests, which are conspicuous for the quantity of boxwood which they furnish. Hence, its coasts were occupied by Greek colonies from an early period, amongst which the flourishing city of Sinope, founded from Miletus about 630 BCE, stood pre-eminent. Amastris, a few miles east of the Parthenius river, became important under the rule of the Macedonian monarchs; while Amisus, a colony of Sinope situated a short distance east of the Halys river and therefore not strictly in Paphlagonia as defined by Strabo, rose almost to become a rival of its parent city. The most considerable towns of the interior were Gangra, in ancient times the capital of the Paphlagonian kings, afterwards called Germanicopolis, situated near the frontier of Galatia, and Pompeiopolis, in the valley of the Amnias river, near which were extensive mines of the mineral called by Strabo sandarake (red arsenic or arsenic sulfide), which was largely exported from Sinope.

Most of this article was rather freely adapted by Leon Aeon from the 1911 Encyclopedia Britannica.