The Newgrange henge: a preliminary investigation of possible astronomical alignment

The Newgrange henge: a preliminary investigation of possible astronomical alignment

Following my discovery (with Ken Williams) of a previously unrecorded henge or ceremonial enclosure just 750m from Newgrange last week, I have been taking a tentative look at the possible astronomical alignment of the monument. There are some interesting initial observations.

I have attempted to ascertain an approximate axial orientation of the "New Henge" of Newgrange using aerial photography. I was able to position my drone in approximate alignment with the "axis" of the monument, using the porch/portal/entrance box and what looked like the centre of the rear or eastern annex. This is, of course, an amateur's efforts to determine a rough orientation and possible alignment of the site, and I look forward to archaeological investigation and more precise imaging which will undoubtedly map the orientation more accurately.

The New Henge of Newgrange. This image has helped me determine a rough axial alignment of the site.

Using the above image, I have attempted to plot the approximate axial alignment of the henge. This assumes certain things, some of which may be considered a leap of faith on my part. But bear with me! 

The National Monuments Service officially added the new henge to their database of monuments today. It has the inglorious label ME026-033----. Personally, I think it should be named New Henge. It is located in the townland of Newgrange, and thus the New Henge of Newgrange. (Other suggested names online have been the Murphy-Williams henge, Dronehenge and I even thought of Clonehenge because it appears in design to be a copy of nearby Site P).

Looking along the rough axis of the site, and using some of the landmarks in the distance, such as trees, to help plot it on Google Earth, I find that the approximate azimuth of orientation (if we accept that the "box" or porch feature on the NW side is in fact an entrance, as hinted at by the National Monuments Service), is 287 degrees. Admittedly this is an approximate figure. We cannot yet deal in precise measurements until a better plan of the monument in the landscape is mapped out.

Our new henge was added to the National Monuments Service database of recorded monuments today.

Looking at the date of the August cross-quarter day (coinciding with the ancient festival of Lughnasa), August 7th, we find that the azimuth of the setting sun is approximately 290 degrees of azimuth. This is not far off our approximate axial azimuth of 287. However, altitude is the key here. The local horizon, viewed from the New Henge, is elevated somewhat because an observer inside the henge looking towards the sunset around Bealtaine/Lughnasa would be looking at the steep southern bank above the River Boyne at Rosnaree. An altitude of seven degrees (in other words, if the sun was extinguished by Rosnaree at an angle of seven degrees) would see the sun's azimuth at 287 degrees.

An attempt to calculate the orientation of the New Henge of Newgrange, from a drone photo of the monument.

Could we be looking at a possible Bealtaine/Lughnasa orientation of the henge? Possibly. All of this should be taken with a pinch of salt until such time as more precise measurements can be taken.

Some significance to this possibility is that Rosnaree was once the site of a (now destroyed) passage-tomb, possibly one of considerable size. The monument was known as Cleiteach or Cleitech in the mythology. It is the place to which Elcmar retired after being deposed of ownership of Síd in Broga (Newgrange) by Oengus Óg in the ancient tale Tochmarc Étaíne, The Wooing of Étain. Furthermore, Cleitech was the location where the High King Cormac Mac Airt died after choking on a salmon bone.

Rosnaree is explored in detail in my latest book.

Of equal or greater significance, mythically, is the fact that the alignment would "look over" the likely location of Fiacc's Pool, that part of the River Boyne where the sacred Salmon of Knowledge was said to have been caught by Finnegas the Druid and its knowledge imbibed by Fionn Mac Cumhaill. (See much more about the mythical significance of Rosnaree/Cleitech in my latest book, Mythical Ireland).

This new discovery (of the New Henge) confirms that there is a row of three henges close to the Boyne. These are: Site P, a previously recorded and very obvious henge or embanked enclosure, which is similar in design and size to the new discovery; the New Henge; and LP2, a henge or enclosure surrounding a passage-tomb, discovered by the INSTAR project in 2010.

The axis of the central henge, the New Henge, appears to point directly across the passage-tomb at the centre of LP2. 

Three henges: LP2 (nearest camera, at hedgerow), the New Henge and Site P.

The broken or segmented double fosse of the New Henge appears replicated, although only in single sections, by the enclosure around LP2. This appears in more detail in our aerial imagery of the cropmarks than it did in gradiometry carried out for the INSTAR project. The row of three henges appears similar in layout to the famous Thornborough Henges in Yorkshire, England. It has been suggested the Thornborough Henges are aligned to represent the stars of Orion's Belt on the ground. This is an interesting possibility for the Boyne Henges and something I will explore in more detail.


The very tentative conclusion of this initial investigation, using what might be described as crude methods, indicates the possibility that the New Henge of Newgrange was possibly aligned so that the setting sun on the cross-quarter dates of Bealtaine and Lughnasa aligned through its entrance and shone along what might be the axis of the monument. This is obviously speculative and approximate. Much more study will be required to determine with accuracy if this might have been the case.

If it was the case, then the site marks the sunsets at the beginning of summer, or the bright half of the year, when the trees have come into full bloom and some of the migratory birds have arrived into the valley (such as the swallow). The land of the area is highly fertile. As farmers, the people of the late Neolithic period knew this very well. They had introduced agriculture to Ireland around 6,000 years ago (approximately a millennium before Newgrange was built). Then, as the summer season progressed and the sun reached its maximum northerly setting point (at summer solstice), as it retreated southwards along the horizon, it might have aligned again with the New Henge at the time of Lughnasa, traditionally associated with the ripening of grain and the gathering of berries – i.e. the harvest. This is highly ironic, as the image of the henge is visible in a field of wheat, and only because of prolonged drought conditions. (See previous post about the henge here).

Another Lughnasa alignment: Cairn S, Loughcrew, at sunset August 7th 2017.

The násad of Lugh (hence Lughnasa) was an assembly or gathering initiated by the Tuatha Dé Danann god Lugh in commemoration of his foster-mother Tailtiú. Was the henge an assembly site for Lughnasa? Was it, in fact, one of the Oenach or assembly sites, as Ronald Hicks has suggested (see Mythical Ireland for more on this). Lugh has a very strong connection with Newgrange because he appeared there to Dechtine and told her she would bear him a son, Sétanta, who later became Cúchulainn, the hero of the epic Táin Bó Cuailnge, the Cattle-Raid of Cooley.

Some comments by archaeologist Steve Davis are interesting in the context of a seasonal assembly. He suggests that these enclosures might have been places where people gathered during the changing of the seasons.

This all points to the idea that the structure was used for ritual ceremonies that involved feasting, gathering and trading together. There is, Davis explains, lots of evidence of feasting on animals at Durrington Walls within the Stonehenge landscape in England, and these sorts of sites are sometimes referred to as passing enclosures – places people congregate at during the changing of the seasons. (Link to article).


It's too early to draw definitive conclusions. This is a hasty and admittedly rough study. But the possibilties are certainly interesting. We could be looking at a ceremonial assembly site on the productive fields by the Boyne with a focus on the summer season, specifically the flourishing of plants and crops and then their harvesting. If the site was oriented the way we think it might have been, then the approximate bearing or azimuth of that axial alignment would coincide approximately with the Bealtine and Lughnasa sunsets, looking towards a place of topographical eminence and indeed mythical importance – Rosnaree/Cleitech. The Bealtaine/Lughnasa sunsets "bracket" the solstice period, and mark that time of year when the sun's setting position moves more slowly (not unlike a pendulum) as it reaches its maximum northerly setting points of the year.

Much more study is needed. But these are exciting times. And this is a wonderful discovery. The henge has "slept" in the land for millennia. It has woken at an interesting time. I look forward with great interest to hearing much more about this fascinating monument from the experts.

Signed prints

If you would to obtain a signed photographic print of the New Henge, you can do so on my secure online shop at this link. It's raining in the Boyne Valley now. A growth spurt might be enough to make the image of this monument disappear. And the wheat will, inevitably, be harvested in August. Ironically, this is at Lughnasa, perhaps at the time when the setting sun would align with its ancient timbers, now long rotted, with only a ghostly image of its former glory to be seen. When it disappears, it might not be seen again for decades.

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