An atlas listing and detailing 4,147 hillforts was released to the public for free on the 22nd June. The atlas gives an exhaustive list of all the known hillforts in Britain, and adds considerably to the previous list of 1,224 hillforts listed in the Wikipedia entry for June 2017. The press release states:
Mostly built during the Iron Age, the oldest hillforts date to around 1,000BC and the most recent to around 700AD. Hillforts were central to more than 1,500 years of ancient living: with numerous functions – some of which are yet to be fully uncovered – hillforts served as communal gathering spaces. The research also shows that, fascinatingly, not all hillforts are on hills; nor are they all forts.
And that is part of the mystery. There are some hillforts, for example, Maiden Castle in Dorset, the biggest hillfort in Europe, that are truly hillforts, not only atop significantly high hills, but with impressive defences, and in the case of Maiden Castle, with clear evidence of attack(s) by the Romans.
Yet there are others that look at first glance as “defended enclosures” to use the archeological term, but are indefensible. They have a bank and ditch, but arranged in such a way that they offer no impediment to attackers. Thornborough Henges is one of the most important examples, and is viewed as being part of a ritual landscape, whatever that means!