The local environment provided a huge range of food and other resources for the settlement at Mountsandel, making it a valuable base for most of the year.
The site was in a rich forest on the upper limits of the Bann estuary, within easy reach of open sea cliffs, and ideally placed on a wide, relatively well-drained plain which would have contained several small lakes. The river was narrower and more easily accessible at this point and, because water levels were higher, was ideally located between freshwater and estuarine environments.
The forest provided the materials to make shelters, tools and weapons as well as fruit, nuts and berries to eat. Wild boar, mountain hare, and a variety of woodland, lakeland, and river birds were hunted nearby. The river provided salmon, eel, trout and bass and the cliffs on the shore were a rich source of flint.