Cahokia, the largest city of the Mississippian mound cultures, lies outside present-day East St. Louis. Land of Water, City of the Dead reconceptualizes Cahokia's emergence and expansion (ca. 1050-1200), focusing on understanding a newly imagined religion and complexity through a non-Western lens. Sarah E. Baires argues that this system of beliefs was a dynamic, lived component, based on a broader ontology, with roots in other mound societies. This religion was realized through novel mortuary practices and burial mounds as well as through the careful planning and development of this early city's urban landscape.

Baires analyzes the organization and alignment of the precinct of downtown Cahokia with a specific focus on the newly discovered and excavated Rattlesnake Causeway and the ridge-top mortuary mounds located along the site axes. Land of Water, City of the Dead also presents new data from the 1954 excavations of the ridge-top mortuary Wilson Mound and a complete analysis of the associated human remains. Through this skeletal analysis, Baires discusses the ways that Cahokians processed and buried their ancestors, identifying unique mortuary practices that include the intentional dismemberment of human bodies and burial with marine shell beads and other materials.