On the Western coast of Ulster (West of Dysert Trade Post)
You’ll need to swim out to the rock then climb up the rock opposite to where the cursed symbol is. If you climb up the right cliffside you’ll find a few arrows if you need them, and then you’ll be able to shoot the cursed symbol from where you grabbed the arrows.
West of Lismore Abbey
You’ll need to find the entrance into the spike-walled camp and then continue inwards until you reach the center where you’ll then be able to shoot the cursed symbol.
You’ll need to head to the small camp near the river and grab the oil pot to explode the breakable stone barricade blocking the entrance into the cave. Once you’ve exploded the entrance you’ll be able to grab the artifact from inside the cave.
This map is found in a house near the river. You’ll need to shoot the door lock from the window on the opposite side of the house and then head into the house to grab the map.
West of Donegal monastery
This map is found in a house west of Donegal. The door is barred so you’ll need to climb up onto the roof and head through a small gap between the taller roof and the wall. Once inside you’ll be able to grab the map from the table.