Peak of Cahokia, Mississippian Culture

Timeline

1. 1141–1145Monks Mound · IllinoisCahokia's Monks Mound approached its final size in the mid-12th century, standing about 30 meters high with a base of over 14 acres, the largest earthen structure in pre-Columbian North America. Large-scale corvée labor organized the hauling of millions of baskets of earth and stone, demonstrating central authority's capacity to mobilize labor and resources.
2. 1141–1150Cahokia site core · IllinoisA stockade wall surrounded the core mound district; the Grand Plaza and the Woodhenge astronomical facility were used for seasonal ceremonies and political gatherings. Shell beads, copper ornaments, and ritual objects in elite burials reflect social stratification and long-distance trade.
3. 1143–1150Mississippi River basin · MidwestCahokia exchanged shell, obsidian, copper, and salt through the Mississippi River and its tributary trade network; Mississippian ceremonial symbols (such as the forked-eye motif) spread to the southeast and Midwest, making Cahokia the most important political-religious center in eastern North America in the 12th century.