Knowth Megalithic Passage Tomb

The Great Mound at Knowth
The Great Mound at Knowth

The Great Mound was built over 5,000 years ago, probably after the construction of Newgrange and before the construction of Dowth. The Great Mound at Knowth is similar in size to Newgrange and is surrounded by 18 smaller satellite mounds. The Great Mound has two passages with entrances on opposite sides, the western passage is 34 metres long and the eastern passage is 40 metre long, ending with a cruciform chamber.

Aerial view of Knowth Images of Knowth.

In this aerial view of Knowth the enclosure on top of the mound is a Medieval Grange, the waterway to the rear is the River Boyne.

Western Passage - Orthostats 48 & 49 Knowth and the other megalithic sites of the Boyne Valley were designated a World Heritage Site by UNESCO in 1993. There is no direct access to the Knowth site, access is by guided tour from the Brú na Bóinne Visitor Centre located close to the village of Donore on the south bank of the river Boyne. Guided Tours of Knowth are from beginning of March to the end of October, for exact dates and more information see Visitor Centre.

George Eogan and his team of Archaeologists began excavating the Great Mound and the smaller surrounding mounds at Knowth in 1962, five years later they discovered the first passage and chamber. Subsequent excavation revealed a second passage and chamber and a collection of decorated stones that comprises a quarter of Western European Neolithic art. More ...

Knowth Kerbstone Secrets from the Grave - Irish Times article where George Eogan talks about uncovering 18 satellite tombs around the great mound at Knowth. They also found evidence of pottery, houses and flint artefacts from a pre-passage-tomb stage of early Neolithic settlement around 4000 BC. More ...

Knowth Kerbstone K15, possibly a sundial or lunar calendar Knowth from The Sacred Island by Martin Byrne.

Engraved Knowth Kerbstone K15, possibly a sundial or lunar calendar. Drawing by Martin Brennan superimposed using Photoshop by Martin Byrne.


Orthostat 47 from the back of the eastern chamber at Knowth Lunar Maps at Knowth - the carvings on orthostat 47 at the end of the chamber in the eastern passage have been identified by Philip J. Stooke as lunar maps. The right-hand section appears to be a map of the lunar maria. The remaining two sections of the carving are simpler but crudely similar to the first, sharing the overall arc shape of the maria surrounding the lunar central highlands as well as an isolated spot representing Mare Crisium.

Orthostat 44 in the western passage at Knowth Knowth from Mythical Ireland by Anthony Murphy.

Calendar stone Kerb stone 52 at Knowth appears to demonstrate that the people of the Neolithic were competent astronomers who had made observations over great periods of time and were able to pass on their astronomical knowledge from generation to generation. The Calendar Stone presents a format that can be used to track the synodic month, and from it we can obtain very important calculations of large subunits of the 19-year Metonic Cycle of the moon.


Knowth Kerbstone 5


There are 124 surviving Kerbstones at the base of the main mound at Knowth. The kerb is roughly circular and measures 80 metres (east-west) by 95 metres (north-south). The Kerbstones are generally oblong in shape and average 2.5 metres in length. More ...

The elevated sun viewed from close to the entrance of the western passage

Equinox sunrise/sunset alignment?

Summary of surveys undertaken by Frank Prendergast and Tom Ray to determine and interpret the alignments of the western and eastern passage tombs at Knowth. The findings indicate that contrary to earlier suggestions, the eastern passage and the western passage are not aligned towards sunrise and sunset respectively at the equinoxes. More ...

Knowth Eastern Passage
Eastern Passage at Knowth.

The eastern passage of the Great Mound at Knowth measures 40 metres, making it the longest megalithic passage in Western Europe. At the end of the passage is a cruciform chamber with a corbelled roof similar in style to Newgrange.
Knowth Plan

Boyne Valley Private Day Tour

Boyne Valley Tours
Immerse yourself in the rich heritage and culture of the Boyne Valley with our full-day private tours. Visit Newgrange World Heritage site, explore the Hill of Slane, where Saint Patrick famously lit the Paschal fire. Discover the Hill of Tara, the ancient seat of power for the High Kings of Ireland. Book Now