What is the name of the river of memory in Frozen II?

The river of memory in Frozen II is Ahtohallan. It is described as a mythical river that preserves memories of the past and helps explain the origins of Elsa’s powers.

Elsa and Anna learn about Ahtohallan through the song “All Is Found,” which their mother, Iduna, sings to them when they are children. Later, Elsa discovers a map aboard her parents’ wrecked ship and follows the route north. She reaches Ahtohallan after crossing the sea with the help of Nokk.

Inside the glacier, Elsa sees magical memories preserved in ice. These visions reveal the truth about the conflict between Arendelle and the Northuldra, including King Runeard’s treachery and the real role of the dam. The film’s warning that “water has memory” connects the river to its broader theme of history resurfacing. Ahtohallan is therefore more than a geographic location: it is a supernatural archive of the world’s remembered events.