Cius

Cius
Cius
Shown within Turkey
LocationAnatolia, in present-day Turkey
RegionBithynia
Coordinates40°25′57″N 29°09′23″E / 40.432468°N 29.156389°E / 40.432468; 29.156389

Cius (/ˈsəs/; Ancient Greek: Kίος or Κῖος Kios) was an Ancient Greek city bordering the Propontis (now known as the Sea of Marmara), in Bithynia and in Mysia (in modern northwestern Turkey). The city was later renamed to Prusias after King Prusias I of Bithynia, who once restored the city.