Sinop Province, south Black Sea coast. The Sinop region is surrounded by Kastamonu province, on the western side, and by Çorum and Samsun districts on the southern and eastern directions. Ancient Regio Pontica also Paphlagonia Region.
The city is located in the central Black Sea Region (41°36′33″N 34°54′07″E), on the thin strip of land (less than 400 m wide in its widest point) of the isthmus of Boztepe, a promontory projecting into the Black Sea and forming together with İnceburun cape the largest peninsula of northern Anatolia, the Sinop Peninsula. The Pontic Mountains run east-west dividing the coastal zone from the inner part of the region and rise up to 1750 m at Zindan Dagi. The hardly accessible nature of the mountains always limited the connection of the city with the inner southern regions and naturally oriented the activities and interests of Sinop toward sea traffic and commerce. On the other hand, the particular geographical shape of the peninsula creates two bays, on the north-west side and on the south-east one. The Akliman natural harbour and Hamsilos bay were already known in the ancient times as natural shelters for ships.