Hellam Township has not been systematically surveyed to determine the locations of prehistoric sites, although four such sites are recorded for the Township in the Pennsylvania Archaeological Site Survey files at the Pennsylvania Historical and Museum Commission. These sites are recorded as a rock shelter designated prehistoric, one Late Archaic/Transitional/Late Woodland site, one prehistoric site and one a floodplain site along the Codorus Creek designated Middle Archaic period.
Historic archaeological sites are represented by ruins or below-ground remains of early historic structures such as domestic dwellings and outbuildings, mills, furnaces, etc. No systematic survey of historic archaeological sites has been carried out in Hellam Township, but the potential for the presence of such sites in the Township is great, given its long and rich cultural history. There are to date four historic archaeological sites recorded in the Pennsylvania Archaeological Site Survey. Two are domestic sites, one is a farmstead and one is an industrial site.