Yal-Tengri

In the fictional world of the Forgotten Realms, Yal-Tengri (also known as the Great Ice Sea) is Toril's equivalent of the Arctic Ocean. It is barely known at all. In the ancient time, the major city on its shore was Winterkeep, it is now the trade city of Naupau, in Sossal. Far in the north of the sea is a small island dominated by a cathedral-like spire, inhabited by gnomes of Gond.

The Yal-Tengri is free of ice for the six summer months of the year

The Endless Ice Sea is the name of the western part of it. Somewhere there is Jhothûn, the long-forgotten capital of a mighty empire of giants.