The Duffy site near New Haven in southeastern Illinois, along the Wabash River, is a major archaeological site that anchors the Duffy Complex on the Illinois side of the river. Inhabited around AD 1000, it is important for understanding the transition from the terminal Late Woodland period toward Mississippian culture. Its most distinctive remains are grog-tempered pottery with little decoration, along with Mounds Stemless projectile points and roughly rectangular celts. The site is related to the Yankeetown Complex but appears to represent a distinct community tradition. It also helps interpret nearby sites, including Carrier Mills and the Illinois Salines, which seems to have been under Duffy control.