If we ask you to imagine a henge, we'd bet your mind instantly goes to the now-iconic Stonehenge in Wiltshire, UK. This prehistoric megalithic structure is, in the minds of many people, the quintessential example of a henge. It’s even in the name, right? Well, not quite. Stonehenge isn’t actually recognized as a true henge, despite giving its name to the classification. This raises a rather obvious question: what on Earth is a henge?   

Slippery definitions

The word “henge” comes from the Old English word for “hang”. So “Stonehenge” was effectively called “hanging stones”, which presumably referred to the lintel stones placed across standing columns to form trilithons (three stones). The term was first applied by British Museum curator Thomas Kendrick who, in 1932, used it to define a site-type (though he did so tentatively). According to Kendrick, a henge was a circular or oval prehistoric monument that used ditches and banks of soil to enclose sacred sites. Entertainingly, this description itself precludes Stonehenge, as its main ditch is external to its main bank. It is therefore a “proto-henge”.

Generally speaking, henges have causeways that give access to their interior. Sometimes there is only one of these entrance points (known as Class I henges), but some henges have two (Class II), or up to four (Class III) ways into the earthwork. Given that these ditches were shallow and located inside the raised banks, it is unlikely henges were used for defensive purposes.

As noted above, a henge is defined by its earthwork structure rather than any particular feature at its center. As such, a henge does not always have stones arranged in its center. Sometimes there are other things there, such as timber posts, monoliths, pits, standing posts, coves, burials, central mounds, and stakeholes. 

Given that most henges are identified through fieldwork or aerial photography of crop marks, it is easy for them to be confused with other prehistoric monuments, such as ring cairns, circular enclosed cemeteries, barrows, enclosed settlements, Roman signal stations, or amphitheaters.

It is also worth noting that a circle of standing stones is not necessarily a henge either. These megalithic structures are far more common than henges and are found across the world.

Okay, this sounds straightforward, but there are also henge sub-types. Firstly, there are “hengiform monuments” that are basically mini-henges with an internal diameter of 15-20 meters (49-66 feet) or less. Then there are the unhelpfully named “henge enclosures” that are much larger than regular henges (usually around 300 meters [980 feet] in diameter).

As our knowledge develops, so too do the words we use to describe things. This is as true for archaeology as it is for any scientific subject. So today, the classification “henge” and its value for demarcating one type of ancient structure from another is very much debated within academic circles.

This is because, over the years, the classification has been stretched to include unusual sites with features that do not match the original intention. As such, the description here is a simplified explanation of what makes a henge.

Where did henges come from and who used them?

So what exactly constitutes a henge is a bit of a messy subject. But surely, we know more about where they came from? Again, not necessarily so. These monuments are surprisingly difficult to date with precision. The earliest examples appear around 3000 BCE, but the larger ones were probably created later, around 2800 and 2200 BCE. Henges and other circles continued to be created through this period and into the Early Bronze Age. However, the larger sites had been abandoned by this point.

There are older structures as well. Standing stones, which are even harder to date, could originate in the mid-Neolithic era – there are postholes near Stonehenge that may date back to 8000 BCE.

Things get even murkier when we start to explore the reasons for their construction. To be sure, there is a ton of speculation, inaccuracy, and fantasy concerning these locations. Contrary to what many New Age groups maintain, there is no evidence that these sites had anything to do with the historical figures known as the Druids. They also had nothing to do with Stonehenge, despite the enthusiasm for the monument among modern neo-Druidic practitioners.

Despite these anachronistic and fabulous claims, it is likely that henges were ceremonial spaces. It is possible the earthwork arrangements marked out specific areas for specific people or for the spirits of the dead. They may have also been the site of ritual practices, such as dancing, drinking, feasting, sacrifices, and funerary rites. However, again, there is no evidence that sacrifices included humans as offerings, unlike at the German Woodhenge.

Other interpretations suggest they may have served judiciary purposes, or been sites of trade or astronomical observation.

Clearly, there is much we do not know about these sites, but that does not mean we can just inject wild unfounded speculation that has little archaeological evidence to support it.

Examples of some henges

It would be impractical to try to examine all the henges scattered across the British Isles. So, here is a selection of some examples.  

One of the greatest examples of a henge is at Avebury, Wiltshire. The site was constructed during the Neolithic period and was altered throughout this time.  

The site is massive, encircling an area that also includes part of Avebury village itself. The henge encloses the largest stone circle in Britain, which originally held around 100 stones. These stones themselves were enclosed by two smaller stone circles.

Another impressive example of a henge, albeit less grand than the one at Avebury, is the one at Mayburgh, Cumbria. Situated close to the motorway, this prehistoric monument has a central area of around 100 meters (328 feet) in diameter and is surrounded by a large bank made up of river pebbles. Some parts of this bank are nearly 3 meters (9.8 feet) tall.

As noted above, the features that make a henge a henge are flexible. As such, Mayburgh henge does not include a surrounding ditch. However, it does include a large single standing stone at its centre.

Finally, there are the stunning structures of the Ring of Brodgar, in Orkney, Scotland. This site includes a henge and stone circle and is part of the UNESCO World Heritage Site known as the Heart of Neolithic Orkney. 

It is the only major henge with a stone circle in Britain that is almost perfectly round. Originally, there were about 60 stones at this site, but today there are only 36. There are also 13 prehistoric burial mounds located at the site.

As mentioned above, there are many other henges across Britain and Ireland that were built during the same period. We may not know exactly what they were created for, but as more examples continue to appear, we are certainly learning more about these impressive – if not confusing – ancient monuments.