The marsh lies along the Heort Creek about halfway between Red Cow Fort and Wandle Bog.
Unlike Wandle Bog, Long Marsh is not sacred, but of little use for grazing, except for some of the special breeds of sheep kept by the Kerenelling. Located in a sump, Long
Marsh is shallow fresh water covered in grasses, rushes, reeds, and sedges. The Sardaling anglers hunt for crayfish and otters here.
White-tailed deer also live in the marsh.