What is believed to be “a giant henge” structure or “causeway enclosure” has been discovered on a tillage farm close to Newgrange in Co. Meath.

The outline of the possible historical monument was uncovered in drone imagery of a large enclosure within the UNESCO Bru na Boinne (Boyne valley tombs) World Heritage Site.

State heritage authorities were informed of the discovery – photographed by author and historian Anthony Murphy and photographer Ken Williams – this week.

Experts say the the extremely dry weather conditions in recent weeks has played a crucial role in the extraordinary sighting.

It is understood that the henge – estimated to measure up to 200m in diameter – could have been built some 500 years after Newgrange, which dates from 3,000BC.

In a statement to AgriLand, the Office of Public Works (OPW) said: “The detailed outline of a large enclosure has appeared as a cropmark which indicates the presence of buried archaeological features.

“The exceptional dry weather of recent weeks is producing some remarkable discoveries such as this one,” the statement said.

Image source: Anthony Murphy

After posting photographs on Facebook, Murphy wrote in a post that he has discussed the discovery with a couple of archaeologists who described it as “very exciting” and “a major find”.

Murphy expressed his shock and excitement writing: “I can’t believe that something this huge has been completely hidden in the landscape and not seen during all the archaeological imaging, and aerial surveys, that have been carried out in recent decades.

If these turn out to be substantial discoveries, then I would be nothing short of utterly elated, chuffed and excited.

The National Monuments Service will now carry out further technical work to help determine the nature of the site.

Image source: Anthony Murphy

A spokesperson for the OPW said: “It is a very significant find which fits within the knowledge of large prehistoric ritual enclosures and associated ritual landscapes at Bru na Boinne.”

The National Monuments Service also thanked Murphy and Williams for discovering and reporting the extraordinary site.