The purpose of the earthen walls that surround the large fields at Fort Ancient is unclear. The ancient ceremonial grounds cover about 125 acres on a hilltop plateau and is enclosed by earthen embankment walls that stand about 5 to 23 feet (1.5 to 7 meters) high. There are as many as 67 gaps between sections of the border walls and between earthen walls that cut across or curve through the grounds as well. These gaps were perhaps ceremonial in nature. Some mounds and gaps seem to show special alignments to seasonal events (such as solstices, equinoxes, lunar cycles, planting, harvesting, etc.). They could also be related to clan lineages, rights of passage, or other purposes, similar to other ancestral and modern Native American cultures throughout North America and elsewhere.
