The longest continuous segment of mound wall at the Old Stone Fort stretches for nearly 2,000 feet between the Big and Little Duck Rivers. Like other sections there, it was built with internal stone cores and soil and rubble fill between and over the cores, and some ground surface preparation appears to have taken place, including a continuous shallow trench cut into the ground between the stone cores. Where the mound has been leveled, the ground-level core of the wall can still sometimes be seen. This mound also crosses a boundary between two different terrains and ecosystems, with open field on one side representing Highland Rim habitat and forest on the other marking the transition to the Central Basin. By living in a region shaped by these transitions, the builders of the Old Stone Fort had access to natural resources from both environments and many opportunities to find food and useful supplies.