The largest earthwork, the "Great Mound", is believed to have been constructed around 160 BCE.
The Great Mound is a circular earth enclosure with an internal ditch and south to southwest entrance.
The earthworks measure 394 feet (120.1 m) across from bank to bank.
The 9-foot-tall (3 m) embankment is 63 feet (19 m) wide at its base, and the ditch is 10.5 feet (3.2 m) deep and 60 feet (18.3 m) across at its top.
 The central platform is 138 feet (42 m) across and was occupied by a 4-foot-high (1.2 m) central mound 30 feet (9 m) in diameter.
One particular mound at the Anderson Site has a sequence of clay platforms, each deliberately covered by a layer of ash.
The largest earthwork, the "Great Mound", is believed to have been constructed around 160 BCE. The Great Mound is a circular earth enclosure with an internal ditch and south to southwest entrance. The earthworks measure 394 feet (120.1 m) across from bank to bank. The 9-foot-tall (3 m) embankment is 63 feet (19 m) wide at its base, and the ditch is 10.5 feet (3.2 m) deep and 60 feet (18.3 m) across at its top.  The central platform is 138 feet (42 m) across and was occupied by a 4-foot-high (1.2 m) central mound 30 feet (9 m) in diameter. One particular mound at the Anderson Site has a sequence of clay platforms, each deliberately covered by a layer of ash.
Mounds State Park