What countries are on the white sea?

It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the northeast.
The whole of the White Sea is under Russian sovereignty and considered to be part of the internal waters of Russia.

What is Karelia?

Karelia is known as “the country of lakes.” One quarter of Karelia’s surface is covered by water including about sixty thousand lakes. The second-largest lake of Europe, Lake Onega, is located in Karelia. The largest lake of Europe, Lake Ladoga, is partly located in Karelia (together with Leningrad Oblast).