Hardings Down is home to three Iron Age sites, which suggests that it was a focal point for communities at that time, along with Cil Ifor. The boundaries of the three site are still clearly visible as turf and bank ditches on the common. The gaps in the banks would have been the entrances to each site.
The western most site is believed to have been a hill fort because of its defensive location. The other two sites are likely to have been less defensive settlements, known as hut platforms (places where houses would have been built). Medieval enclosures around the sites suggest that the area continued to be settled until the Middle Ages.