Giant old-growth trees now cover the Fort Hill earthwork. Tangled among their roots are masses of now-broken sandstone slabs, once part of an elaborate construction process. Retired Ohio Historical Society Curator Martha Otto explains:

There was work done there in the 1960s to investigate a section of the wall, and to determine that there was an inner core of blocks of stone, in kind of a triangular shape, and then to provide the ballast for the wall itself. So it wasn’t just a bunch of earth piled up, but there was an intentional plan for making sure that the wall would be secure and stay in place. In fact, it has for two thousand years.

Two parallel walls were built, around the rim of the plateau, with both earth and stone. Then both were capped and unified by the final layer, up to 15 feet high, and surfaced with carefully shaped and fitted sandstone slabs, taken from the top of the plateau.