Siutghiol is a lagoon on the shores of the Black Sea, in Constanța County, Northern Dobruja, Romania. It has a length of 7.5 km and a width of 2.5 km; it extends over 20 km2 and has a maximum depth of 18 m. Ovidiu Island is a small island on the west side of the lake, 500 m from the town of Ovidiu. On the east side of the lake is the resort town of Mamaia, which lies on a strip of land 8 km in length and only 300 m in width, between the Black Sea and Lake Siutghiol.

Etymology

The name of the lake comes from the Turkish Sütgöl, meaning "the milk lake".