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Concentric circles Fourknocks megalithic mound, Naul, Co. Meath Concentric circles

Rare photo of PJ Hartnett at Fourknocks
A rare photo of excavations at Fourknocks in the 1950s. Do you recognise this man? Click to see larger image.

The name Fourknocks comes from the Irish 'Fuair Cnocs' which means 'The Cold Hills'. The mound is part of a complex of small sites in the area, and is significant to Newgrange because it is aligned with the line of Winter Solstice sunrise from Newgrange. Strangely though, the Fourknocks mound is not visible from Newgrange.

The mound (known as Fourknocks Site I) was excavated along with the nearby Site II in the 1950s by P.J. Hartnett. The site was reconstructed with a metallic domed roof, although no roof was found during excavation. Near the centre of the floor was found a posthole which it has been suggested may have formed a support for a wooden roof on the mound.

A number of individuals were interred in Fourknocks, with deposits of cremated and inhumed remains found in both the passage entrance and in the chamber.

Passage lintel stone at Fourknocks
A photo of the lintel which originally sat over the passage. See photo gallery.

Zig-zags are a prominent feature on many engraved stones from the Neolithic. This stone was originally found over the interior of the passageway, but has now been placed to the left of the entrance.

Antler Pin

This amazing antler pin was found at Fourknocks. It was made by splitting the shed tine of a young deer, and is D-shaped in cross section. It is 19mm long and has a slightly expanding domed head. (Knowth and the passage-tombs of Ireland, George Eogan)

"The ornament consists of a chevron pattern on the rounded part of the body, formed by cutting. Care was taken in its manufacture and the surface was well-polished, even extending into the cuts."

The Fourknocks chamber is 41.92 sq. metres in size, considerably bigger than those at Newgrange (16.50), Knowth East (20.21) and Dowth South (15.21). In relation to the overall size of the chamber, the recesses at Fourknocks are small, and so too is the passage, with an area of just 5.67 sq. metres compared with 14.78 for Newgrange and about 30 sq.m. for Knowth East.

Fourknocks Plan Click here to buy Landscapes of Neolithic Ireland

According to Eogan (1986), there was a small patch of paving in the passage at Fourknocks. Sod or boulder clay was used in the construction of the mound, and small stones were 'grouped together' to form a 'symbolic kerb'.

Most of the orthostats and roof lintels at Fourknocks are carboniferous limestone, which may possibly have been brought to the site from nearby outcrops. Apart from one example, all the decorated stones at Fourknocks are green gritty sandstones.

Detail on recess stone
Detail on the stone over the southern recess at Fourknocks.

The large size of the chamber of Fourknocks meant it would be difficult to envisage a beehive-style stone roof on the structure. P.J. Hartnett, who excavated the site, suggested the roof was finished by using timbers supported on a central post. There was, of course, a post hole found in the centre of the chamber floor, but whether this indicates the presence of a wooden roof is open to debate. Some believe the roof may have been made of a tarpaulin of cow-hide or similar material. Others believe the chamber was never roofed. Because the passage of Fourknocks is oriented to approx. 20 degrees east of north, it does not point to a sunrise or indeed a moonrise, so an astronomical function would probably have involved the stars.

The western recess
A general view showing the Western recess at Fourknocks.

The presence of zig-zag patterns on a number of stones in Fourknocks is suggestive of the W-shaped constellation, Cassiopeia, which would have been visible through the Fourknocks passage between 3000BC and 2500BC, around the time the site was constructed. Martin Brennan (The Stones of Time) has suggested that quadrangles and zigzags could be images of star fields. He says the association of quadrangular patterns and stars is common to many cultures. See this page for an astronomical explanation for some of the symbols of the Irish Stone Age.

Chamber of Fourknocks
A view of the chamber of Fourknocks. For more pictures, click here.


We believe the passage was also oriented towards the rising of another important star, Deneb, which is the bright 'tail' star of the constellation Cygnus. This may have been a precessional calculation, given that around 3,000BC, give or take a few centuries, Deneb and Cassiopeia are at their lowest elevation. This is the only time in the whole 25,800-year precessional cycle when these constellations are not circumpolar. For the rest of the cycle, they do not set below the horizon from this latitude. Perhaps the builders of Newgrange and Fourknocks knew this.

The passage of Newgrange points to Fourknocks, although neither site is intervisible. Also, Cygnus is distinctly cruciform in shape, just like the passage at Newgrange. The legend of the romance of Aonghus (who owned the Brugh) and Caer tells how Caer was a swan, and after Aonghus fell in love with her at the "Lake of the Dragon's Mouth" (possibly the constellation Draco), they flew back to Newgrange and lived "in the Brugh" after that.

If we consider that Newgrange points to Fourknocks, and that Fourknocks in turn points to the rising place of the "swan star" Deneb, we see that the building of these sites may have been part of some great astronomical construct, designed to capture a specific moment in astronomical time in such a way that it demonstrates the people of the Neolithic were acutely aware of the great cycle of precession.

Furthermore, the presence of a large flock of wintering Whooper Swans at Newgrange every year may add further weight to the "Cygnus Enigma". There are a number of ancient legends which connect swans with Newgrange, including the romance of Aonghus and Caer, and the conception of Setanta (Cuchulainn) at Newgrange by Dechtine and Lugh, in which story Dechtine arrives at Newgrange with other maidens in the form of swans. This story takes place during winter time, which is suggestive of the solstice. The story of the fate of the children of Lir tells how the Milesians, so moved by the plight of the swans, introduced a law in Ireland that no swan was to be harmed.

Another astronomical significance of the swan constellation is the fact that Deneb is a good marker for the position of the sun on the night before Winter Solstice.

Fourknocks with no roof.
A rare photograph of Fourknocks taken after excavation but before the modern metallic domed roof was placed on the structure.

A spiral carved on a chamberstone at Fourknocks. The spiral is a universal symbol at the ancient stone sites, and can be found in abundance in the Boyne Valley passages, especially Dowth, Knowth and Newgrange.

Circles and spirals . . . Neolithic carvings at Fourknocks. This stone is located just inside the passage. Click here for photo gallery.

The entrance to the Fourknocks mound. Access to the mound is along a narrow pedestrian path from the nearby road.


The key for the entrance door to Fourknocks Passage Tomb can be obtained from Mr. Fintan White +353 (0) 1 8354722 before 6pm who lives over a mile from the Tomb. Directions are signposted from Fourknocks.His house is found west of the tomb - turn left at the Y-junction with the white and green house then keep going straight up the narrow track where the main road turns to the left. The Whites' house is some distance up here - the 5th on the right. A cash deposit must be given which is refundable on the safe return of the key. The key should be returned before 6pm.


If you'd like to take a tour of Fourknocks, perhaps as part of a bigger tour of the Boyne Valley area, Mythical Ireland Tours would be happy to try to facilitate you. Cick here to enquire about a Fourknocks tour or visit our Tours section to see more about the tours we offer.


Fourknocks ridge "tower" site shares a unique alignment with Baltray standing stones and Rockabill island. Suggested books: Landscapes of Neolithic Ireland - Gabriel Cooney; Knowth and the passage tombs of Ireland - George Eogan; Other books.

Notice: Some photographs are copyright © Eileen Roche, 1996. Images may not be copied, reproduced or redistributed without the prior written consent of Eileen Roche.


All information and photos, except where otherwise stated, copyright, © Anthony Murphy, 1999-2015
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