The northern land ruled by Louhi in the Kalevala is Pohjola.
Pohjola is the mythic Northland and one of the two great opposing realms in the epic, alongside Kalevala or Väinölä. It is presented as a distant, wealthy, and dangerous kingdom whose inhabitants repeatedly clash with the heroes of the southern land.
Louhi is the powerful mistress of Pohjola, often described as a witch-queen. She controls the Sampo after Ilmarinen forges it, sets difficult tasks for would-be suitors to her daughters, and later causes disasters when the Sampo is taken from her.
Pohjola is not always a precise geographical location. In older Finnish and Karelian traditions, the name can also refer to a distant northern region or even the realm of the dead, sometimes overlapping with Tuonela. That variation explains why Tuonela may appear in related mythology, but in the Kalevala’s political and heroic stories, Pohjola is Louhi’s domain.