The history of Britain's secret hillforts and best places to see

Ancient earthworks steeped in mystery wind around the summits of many prominent British hills. Who built these strange structures, and why? Here is our expert guide on the history of hillforts in Britain and the best sites to visit

16th January 2018
Hill fort England

You can get a hair-raising feeling of closeness to the past as you stand on the airy ramparts of Mam Tor, the 2,000-year-old hillfort that dominates the head of the Hope Valley in the Peak District. 

As you look east down the broad, tree-lined valley and north to the frowning heights of Kinder Scout, you are experiencing the same sense of dominance of the landscape as our ancestors who built the fort must have felt. This is especially true on a winter’s morning when mist fills the valleys and the earthworks are more sharply defined now the cloaking vegetation has died back. 

Mam Tor Peak District
Mam Tor, Peak District - one of Britain's oldest and most impressive hillforts/Credit: Getty

Mam Tor is one of our most impressive hillforts, dating from the late Bronze to early Iron Age. Its embankments were built to abut onto the collapsed ‘shivering’ east face, thought to have formed part of the ancient defences. 

Hillforts are little understood by most people, perhaps due to the militaristic name that the Victorians gave them. In fact, Mam Tor and many others seem to have been peaceful summer shielings, used by Celtic tribes to watch over their flocks. They would probably have been abandoned during winter months. But in others, such as Maiden Castle in Dorset and Danebury in Hampshire, there is evidence of an Asterix-style resistance to the Roman invaders.

How many hillforts are there in Britain?

Oxford University has published an online atlas of hillforts that doubles the number thought to exist. It has identified 4,147 hillforts in Britain and Ireland, where formerly the number was thought to be 2,000. There are 1,694 in Scotland; 1,224 in England (271 of which are in Northumberland); and 535 in Wales.

Maiden Castle Dorset
Aerial image of Maiden Castle, an Iron Age hill fort, Winterborne Monkton, near Dorchester, Dorset/Credit: Getty

So how and why were these enigmatic structures built? The construction of a hillfort was a massive engineering and logistical task. It has been estimated it would take 150 men about four months to construct an eight-acre enclosure with a single bank and ditch, using nothing more than antler picks, wooden spades and woven baskets to transport the soil. 

The method of construction is illustrated at Ladle Hill, an unfinished hillfort near Newbury, Berkshire. It isn’t known why it was abandoned but archaeologists are grateful, as it reveals how hillforts were built. It appears that gangs of workers were used to deepen and widen an initial encircling shallow ditch in sections. 

Wooden palisades were often constructed first. Around these, embankments and gateways – often with intricate interlocking entrances such as those at Maiden Castle – were designed to give the defenders maximum advantage against potential attackers. Archaeologists still argue about the purpose of hillforts. They seem to be most common in disputed areas, such as the Welsh Marches and Northumberland, where in the College Valley, every hilltop seems to be crowned by a hillfort, each visible from its neighbour. This would support one theory – that they were the Iron Age equivalent of a nuclear deterrent, warning off opposing tribes or potential invaders.

Basic defences

When Roman commander Vespasian (later emperor) was sent to ‘subdue’ southernBritain in AD43, he attacked a string of about 20 hillforts. The Celts’ main weapon of defence appears to have been simple slingshots and spears. At Danebury, a collection of more than 10,000 slingshot stones were discovered and the skeletons of severely injured bodies have been found buried in ditches there and at Maiden Castle. One, in the Dorchester museum, has a Roman ballista bolt embedded in its backbone.

Many hillforts have hut circles in their interior, such as at Danebury, Tre’r Ceiri on the Llŷn Peninsula and Croft Ambrey in Herefordshire. The circular thatched huts were simple one-roomed homes made of wattle and daub. They would have been inhabited by people much like us, grumbling about their neighbours and the weather, or arguing over a missing sheep or pig.  An open hearth stood at the centre of the hut; beds were made of straw covered in animal skin.

Iron Age economies were essentially pastoral, with livestock moved to the uplands in summer and down to the lowlands in winter for more sheltered grazing. Crops of emmer and spelt wheat, barley, rye and oats were grown in small, enclosed fields in the lowlands, and evidence has been found of storage pits for these grains in some hillforts.

The Roman Invasion signalled the beginning of the end for hillforts, although some, such as Hod Hill and Maiden Castle, were reused by the invaders as sites for forts or temples. Among the many things the Romans did for us was to construct roads, towns and an urban culture, and those Iron Age castles in the air were gradually abandoned to become the evocative, lonely monuments they are today.

As archaeologist James Forde-Johnson wrote in 1976: “Of all the earthworks that are such a notable feature of the landscape in England and Wales, few are more prominent or more striking than the hillforts built during the centuries before the Roman conquest.” 

Britain's best hillforts to visit

Ingleborough , North Yorkshire

Inglesborough Hillfort, North Yorkshire
Inglesborough Hillfort, North Yorkshire/Credit: www.lastrefuge.co.uk

A daunting hillfort of the Brigantes, the Celtic tribe that once controlled much of northern England. Their queen Cartimandua allied herself with the Romans, but her ex-husband Venutius rebelled twice against her and the Romans before his defeat in 69AD. This was the scene of his last stand. The 15-acre fort tops a popular Yorkshire summit – one of the Three Peaks – with views as far as the Lakeland hills and Morecambe Bay. 

 Tre’r Ceiri, Llŷn Peninsula, North Wales

Tre'r Ceiri, Llŷn peninsula/Credit: Jason Hawkes
Tre'r Ceiri, Llŷn peninsula/Credit: Jason Hawkes

Some of the drystone walls of Tre’r Ceiri (‘The Town of the Giants’) on the beautiful Llŷn peninsula stand an impressive
5m high, and the 150 hut circles within the ramparts could have housed up to 400 people. There are stunning views towards the mountains of Gwynedd.

Hambledon and Hod Hills, Dorset

Tre'r Ceiri
Hambledon and Hod Hills, Dorset/Credit:Getty

Hambledon is a magnificent multi-banked hillfort that winds sinuously around a chalk outlier overlooking Blackmoor Vale. It was built almost 5,000 years ago, using antler picks, and abandoned around 300BC. Its southern neighbour Hod Hill is about half its age, and includes the only known example of a Roman fort superimposed on a native hillfort.

 British Camp, Malvern Hills

British Camp, Malvern Hills
British Camp, Malvern Hills/Credit: Alamy

A beautifully built, multi-banked hillfort that contours around the Herefordshire Beacon at the southern end of the rolling Malvern Hills. Built in the 2nd-century BC, its scale is awesome, enclosing an area of 44 acres. It was later topped by a Norman motte-and-bailey castle mound known as The Citadel. 17th-century diarist John Evelyn called the view from the hill “one of the godliest vistas in England”.

Danebury, Hampshire

Danebury, Hampshire
Danebury, Hampshire/Credit: Alamy

High on a wooded chalk knoll near Andover, this is probably the most thoroughly examined hillfort in Britain. Archaeologists have pored over it for more than 50 years and found extensive field systems in the surrounding landscape. It is believed to have been inhabited for 400 years, from 550 BC, housing hundreds of people.

Mither Tap, Bennachie, Aberdeenshire

Mither Tap, Beninachie, Aberdeenshire
Mither Tap, Beninachie, Aberdeenshire/Credit: Getty

“They create a desolation, and they call it peace.” So said Caledonian chieftain Calgacus before the fateful final battle
of Mons Graupius with the Romans in AD 84, according to Roman historian Tacitus. The battle is thought to have been fought on the slopes of Mither Tap, the hillfort-topped easternmost summit of the five-mile Bennachie ridge.

Cadbury Castle, Somerset

Cadbury Castle, Somerset
Cadbury Castle, Somerset/Credit: Getty

The fabled site of King Arthur’s Camelot, Cadbury Castle is a late Bronze and Iron Age hillfort five miles north east of Yeovil. Its four terraced earthwork banks and ditches stand 500 feet above the low-lying Somerset Levels, and have revealed evidence of vigorous resistance to the Roman invasion of AD43.

Caer Caradoc, Shropshire 

Caer Caradoc, Shropshire
Caer Caradoc, Shropshire/Credit: Getty

The site of Celtic leader Caractacus’s last stand against the Romans, Caer Caradoc dominates the Church Stretton valley in the heart of the Shropshire Hills. This six-acre hillfort encloses a spur of the 460m, volcanic crag-rimmed summit, where a shallow cave is said to have given Caractacus shelter. 

Maiden Castle, Dorset

Maiden Castle Dorset
Maiden Castle, Dorset/Credit: Roger Smith

Surely the grandmother of all British hillforts, Maiden Castle, overlooking Dorchester, is one of the biggest (it covers 47 acres), best-known and most impressive. Evidence has been found of an attack by the Romans, who later built a temple at its heart. www.english-heritage.

How to find hillforts in your local area

Seek out your local hillfort to share the feeling that people millennia ago surely experienced – that they were monarchs of all they surveyed. Visit: hillforts.arch.ox.ac.uk

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