In 1940, Gretchen Cutter and a WPA crew conducted excavations in the Mound Wi°5 at the Fisher site in Will County, Illinois. We examined those materials as part of our reanalysis of the Fisher site excavations by George Langford and the University of Chicago. The mound’s material culture correlates with the Des Plaines phase but contains strong connections to the east, especially with Albee phase mortuary practices. Calibrated 14C dates and Bayesian modeling place the Des Plaines phase as contemporary with the Mound Wi°5 mortuary’s primary use during the ninth to eleventh centuries. There is isotopic evidence of a mixed C₃/C₄ diet with some maize consumption. Mound Wi°5 represents the only Terminal Late Woodland collective mortuary facility currently known in northeastern Illinois. The identification of such multigenerational communal Terminal Late Woodland mortuary practices lends support to the contention that they provided the cultural base for the emergence of the distinctive Langford Tradition accretional mortuary mounds.