Ionia, Herakleia ad Latmon, 150-142 BC, AR Tetradrachm (16.48g, 32mm)

Ionia (/aɪˈoʊniə/ eye-OH-nee-ə)^[1] was an ancient region on the western coast of Anatolia, to the south of present-day İzmir, Turkey. It consisted of the northernmost territories of the Ionian League of Greek settlements^{[citation needed]}. Never a unified state, it was named after the Ionians who had settled in the region before the archaic period^{[citation needed]}.

Ionia proper comprised a narrow coastal strip from Phocaea in the north near the mouth of the river Hermus (now the Gediz), to Miletus in the south near the mouth of the river Maeander, and included the islands of Chios and Samos. It was bounded by Aeolia to the north, Lydia to the east and Caria to the south. The cities within the region figured significantly in the strife between the Persian Empire and the Greeks.