In February and March 2008, an unusual Mississippian building was identified and excavated on an isolated hilltop at the edge of the Richland Complex in the uplands 11 km east-southeast of the well-known Cahokia site. Based on its architectural attributes, mode of abandonment, artifact assemblage, and plant remains, we infer that it was a special residence, or medicine lodge, connected to a nearby Stirling phase settlement and, ultimately, to Cahokia. This T-shaped building possessed a unique interior alcove that, along with a second rectangular building, was aligned with the winter solstice sunrise. Sometime during the Stirling phase, both buildings were burned and the remains left exposed to the elements until the structural basins silted shut. [ABSTRACT FROM AUTHOR]