Duncan Farm, near Grafton, Illinois, is a Woodland period archaeological site with a habitation area and two burial mounds. Recognized on the National Register of Historic Places, it is significant for its link to the Hopewell exchange system in Illinois. As the nearest neighboring village site to the Golden Eagle regional transaction center, a major trade and social hub, it may itself have functioned as a local transaction center within that network. Its two large mounds and the site’s clear stratification, which helps archaeologists date artifacts, strengthen its importance for understanding regional trade and settlement.