The Naples Archeological District on the east bank of the Illinois River at Naples, Illinois, includes sixteen archaeological sites occupied mainly during the Woodland period. It reached its greatest importance in the Middle Woodland period as a significant trade center in the Hopewell exchange system. More than a dozen mounds still remain, most used for burials and some also containing refuse. Several large village sites accompany the mounds, indicating that Naples was both a center of exchange and a settled community. The district was added to the National Register of Historic Places on December 22, 1979.