The Turin Pit locality (Monona county, Iowa) has been known to paleontologists since 1908, yet the age of the fauna has been unclear. Early paleontologists considered Turin Pit to date to a pre-Illinoian interglacial (the “Aftonian).” Subsequent researchers suggested it dated to the last glaciation. This study provides a partial list of mammals in the Turin Pit fauna, and together with stratigraphic information, uses the known age ranges of taxa to estimate an age for the assemblage. The presence of Mammuthus, Aenocyon, and Castoroides combined with a magnetically-reversed till located stratigraphically above fossil-bearing deposits, suggest the Turin Pit assemblage dates between ~1.3 and 0.773 Ma. The fauna can be assigned to the Irvingtonian North American Land Mammal Age based on Mammuthus, Aenocyon, Castoroides, and Ondatra zibethicus annectens. This fossil assemblage provides a rare window into the Quaternary paleontology of Iowa that pre-dates the Illinoian glaciation.