Archaeologists cite three reasons why Fort Ancient is not a fortification: there is no evidence that a large number of people lived inside the earthworks, certainly not the thousands needed to defend such a large area; the earthen walls have 67 openings with no known way to close them; and the ditch lies on the inside of the walls rather than the outside, where it would be an effective defense. The purpose of the interior ditch remains unknown. It probably provided soil for constructing the earth walls and may have been only a borrow pit. It may also have served as a water collection area, as early records indicate that a spring once fed water into the ditch, and water has also been suggested to have had an important symbolic relationship with American Indian religion.