Hillforts in the Chilterns

Since prehistory, humans have been leaving their mark on the landscape, whether to claim dominance or just for art’s sake.

In the Chilterns, some of the most prominent leftovers from our prehistory are iron-age earthworks. Created for a variety of reasons – from keeping livestock, to showing off status – these mounds, ditches and remnants are often called ‘hillforts’, conjuring up pictures of large fortifications loftily surveying the landscape, ready to defend those inside. But this title is a little misleading. It actually covers a whole range of prehistoric enclosures, many of which aren’t on top of hills and show no evidence of attack. It just so happened that many early archaeologists were military men, so automatically jumped to the conclusion that the works they uncovered were fortifications. This is clear in some of their names: for instance, Caesars Camp was thought to have been constructed by Caesar during his military campaign. Yet, these earthworks date back much further than the Romans, to the late Bronze Age to Middle Iron Age: 1100 BC to 300 BC.

What is a hillfort?

Hillforts were an important part of Iron Age life, but they have a very varied story – there’s no such thing as a ‘typical’ hillfort! They can range in size from around 10 ha with multiple enclosed earthworks, to under 1 ha in size and only single earthworks. There are many different shapes and forms, but they do all have two common characteristics:

  • They can be found at significant or prominent places in the landscape, such as on hillsides or hilltops, near watercourses, or at route nodes, where trackways met.
  • They are all enclosed in some way by ditch and bank earthworks, where people moved the earth to create formations.

The construction of hillforts varied and was often dictated by both the geology and the groups of people building them. To create the ditches and banks, people would dig into the earth and pile the spoil up to make a bank. Some hillforts have evidence of ‘box ramparts’, where posts and fences would have held the spoil in place until it consolidated. This stopped the bank from simply falling away after a short period of time. Many of the banks may have had wooden fences or palisades built on top of them to keep livestock in, or neighbours out.

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Bulstrode Camp

Where are hillforts found?

Iron Age hillforts can be found across north-western Europe, from the UK to Poland. A recent survey of hillforts in the UK and Ireland found more than 4,000, varying in size, function and location. There are some places with denser concentrations, such as the Chilterns, probably because reliable water sources and fertile soils attracted more people to the area. Indeed, the Chilterns AONB has the tenth densest concentration of hillforts in the UK.

On the other side of the world, there are a set of features in New Zealand built by Māori people that look almost exactly like our hillforts! But they were constructed much later, beginning around 900 AD, with the last ones built in the 19th century.

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Walk in the footsteps of ancient people

Hillforts to visit in the Chilterns include those at: Ivinghoe Beacon; Pulpit Hill; and Wendover Woods. Or take a look at our interactive map for more inspiration about where to go for heritage and history, and take a walk through time.

How do we know how old hillforts are?

It’s not easy to get a ‘good’ date from a hillfort or earthwork, so estimates are made using shape, size and location, and comparisons with other sites. Often, a sherd of pottery can be all that dates a site; the best dating estimates come from radiocarbon dating of organic remains within the earthworks, but this still only provides a ‘window’ within a couple of centuries.

Who made hillforts and why?

There are many different reasons for why hillforts were built, but it is most likely that those living and working around the area they appear in created them. Reconstructions often show them as bustling little towns on top of hills, but most sites show no evidence of any roundhouses or village life. It is more likely that hillforts were made by those living in the landscape around the site and were built as a community effort, perhaps as somewhere to gather for a fayre, for refuge or to swap livestock. Yet, the most stand out reason for building them appears to be as a status symbol – local people demonstrating their dominance or influence over the landscape around them.

Eventually the building of hillforts waned. People found different ways of expressing their communal identity and impact on landscape. As the Romans appeared, so power systems shifted from small communities to larger groups and influential people, who ultimately took control over huge swathes of land. During these later periods, some hillforts were reused and repurposed, but many were just left to nature.

What is so special about these places?

Humans have had an impact on Britain for thousands of years, the evidence of which is everywhere, but not always easily seen or understood. Yet, hillforts are very obvious monuments that anyone can visit and marvel at. Whether windswept downlands with stunning vistas, or secretive and shaded woodlands, these sites can feel as special to us now as they once were to ancient people, giving us an affinity to those that lived there, and allowing us to walk in their shadows.

Are our hillforts threatened?

Most hillforts are Scheduled Monuments, affording them protection under the law. Yet, they may still be the target of ‘heritage crime’ – activities that disturb, spoil or destroy the monument. Anything from vandalism to disturbance by metal detectors is prosecutable by law, but many hillforts exist in remote areas where damage goes unseen and unchecked.

Other threats to our hillforts include encroaching development, fly-tipping and erosion from large numbers of visitors – at Ivinghoe Beacon, for example, a long, white scar has developed in the chalk hillside where people have walked.

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View of Ivinghoe Beacon showing footpath erosion

Keeping hillforts and ancient sites safe

Everyone can help to keep our ancient monuments safe by looking out for anything that should not be happening, such as fire-lighting or bike-riding, and reporting it. The Chilterns Conservation Board (CCB) helps to preserve hillforts, raising awareness about their special qualities and why it is so important to look after them.

Spread the word: hillforts are fantastic! They were special to the people that built them, and they should be special to us too!

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Beacons of the Past

The Beacons of the Past project has been running since 2018, bringing Chilterns’ hillforts into the spotlight. Funded by the National Lottery Heritage Fund, the project commissioned the largest high resolution LiDAR survey (laser scanning) ever flown for archaeology in the UK – one new hillfort was discovered, and lots of new archaeology was found, including Iron Age and Roman enclosures, World War I training trenches, and Medieval field systems.

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Discover the timeline of the Chilterns

There has been a rich and varied geology and history in the Chilterns – from the Cretaceous Period, when shallow seas laid down the distinctive chalk of the area, right up to today’s working landscape.
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Volunteering hub

Find out more about volunteering in the Chilterns - indoor, outdoor, practical or desk based there's something for everyone, whatever age or stage! Use our interactive volunteering hub to find the perfect opportunity for you.
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Outstanding Chilterns Magazine

Jam-packed with news and updates from the Chilterns National Landscape, now available to read online or find out where to get a printed copy.
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About us

Find out all about the Chilterns Conservation Board, our staff and our publications.
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