Monks Mound

Monks Mound is the largest prehistoric earthwork in the Americas, with a base covering over 14 acres, a height of 100 feet at its highest point, and an estimated 22 million cubic feet of earth hand-carried in baskets from borrow pits throughout the Cahokia site. It was built in a series of stages rather than all at once, mostly from AD 950-1200, with core-drillings suggesting eight to 14 building stages, and construction beginning around AD 950 and enlargements continuing until AD 1250. Excavations have found indications of a stairway on the South Ramp; several buildings and a small mound rebuilt eight times on the First Terrace; a large temple structure on the Fourth Terrace; evidence of a French chapel and historic Indian occupation in the 1730s on the First Terrace; and the Birdman Tablets on the east side of the mound. Recent tests confirm that the First Terrace was a late addition to the front of the mound, and drilling deep beneath the Second Terrance encountered a large mass of stone cobbles whose function remains unknown. The Mississippians also used soil engineering, selecting and placing specific soils for strength or drainage. The mound took its name from a group of French Trappist monks who lived on a nearby mound from 1809-1913 and planted gardens, fruit trees, and wheat on its terraces. The Birdman Tablet, discovered in 1971 on the east side, is an engraved sandstone tablet showing on one side a man in a falcon dancer outfit with a beaked mask and wing and on the reverse a cross-hatched diamond pattern representing a snake. The Fourth Terrace building was probably the residence of the leader and the religious and political focus of this urban center, enclosed by a fenced courtyard with a huge post in the center. In the 1830s Amos Hill built his farm complex on the Third Terrace, removed a small mound on the southeast corner, and was buried on the northwest corner of the Fourth Terrace.

Collinsville, Illinois · United States