Swamp is an area on the British map and should not be confused with the Marsh on the Denmark map. This area is added to the map during the quest The Mercian Connection. The area is northeast or northwest from Eoforwic (York) and Scarborough respectively.
Cairn, cross and runestone
The runestone can be found south in the area. The cairn can be found southwest in the area near the abandoned tent, while the cross can be found near the tower in the middle of this area.
From the Swamp, it takes: