Suspected Alignment / Alignments:  Equinox Sun-rise / Sun-set
Site Type: Passage Tomb
Irish Grid Ref: N9963373439
Location: Link to Bing Maps

Sunset at Knowth Passage Tomb


This passage tomb is described on as follows;

"Knowth cemetery, site 1. This great kerbed mound is the focal point of a large passage-tomb cemetery, which has been the site of extensive excavations since 1962. Sixteen small passage-tombs are in close proximity to the main mound and another (ME019-030007-) is 120m to the W. The central mound is c. 90m by 80m by 11m in H. Incurving of kerb to E and W indicates entrances to two back-to-back passage-tombs. The W tomb, 34.2m long, comprises a bent passage leading to a simple square chamber; a stone basin lies at bend in passage. The E tomb, 40m long, contains a cruciform chamber with corbelled roof; N recess contains an elaborately decorated stone basin. Many of the kerb stones and large numbers of the structural stones of both tombs are decorated with megalithic art. (Eogan 1986)."

This passage tomb is one of the three great passage tombs that make up Bru Na Boinne. It is the largest of the passage tombs and also likely to be the "youngest" of them. As above extensive excavations have taken place since 1962. Before they begun it was not know whether there were any passages within the mound. It was not till 1967 that the two long passages were discovered. Knowth has been reused a number of times since it was originally constructed, during the Iron Age it was fortified as a residence of the Kings of North Brega.
In Martin Brennans book "The Stones of Time" he proposes that the passages are aligned to the rising and setting sun on the equinox. Some damage has occurred to the passages over the years but Martin Brennan and his team did observe the sun entering the chambers around the equinoxes in the early 1980s. They also proposed that the standing stones at both entrances act as a kind of sun-dial, casting a shadow onto the highly decorated entrance stones. Frank Prendergast and Tom Ray have recently written a paper showing that the alignments to the equinoxes are not exact Link to paper "Alignment of the Western and Eastern passage tombs" . I have attached a number of links below for further information.

Links to photographs;
Link to a picture of the shadow casting phenomena at Ken Williams website (half ways down the page)
Link to a picture of the shadow casting phenomena at Anthony Murphys website

Links for further information;
Information on Knowth at
Information on Knowth at
Information and pictures at