Forgotten Caverns. After the second water drop in the lake, head to the newly exposed beach northwest of Tyr’s Temple. In the same beach, you’ll find a spirit that will start the favor “Dead Freight”.
Enter the cave and destroy the two wolves feeding on a corpse. There’s a dead-end path to the left with another wolf and wooden chest. The map is lying on the ground in front of the chest.
Inside the Northri Stronghold, you’ll have to open the gate by destroying the chain holder around the water wheel. This will free the water wheel and open the two large gates ahead. Before taking the boat, climb the tower in between the gates to find the treasure mound on the ledge there, along with a bag of hacksilver.