A petition to have the proposed M3 motorway rerouted away from the acclaimed Hill of Tara site has been delivered to the Minister for Environment.
The Save Tara Skryne Valley group says the proposed 49-kilometre route between Navan and Dublin, which passes within two kilometres of the site, will ruin "Ireland's oldest and most revered national monument".
The group this morning delivered a 10,000-strong petition alongside a written submission from campaigners, including international historians and archaeologists to the Department of Environment.
In the submission, the group says the archaeological importance of this area is "beyond question" and claims the planned motorway "will impact at least 141 known sites".
A spokesman for the group, Mr Vincent Salafia, said: "It is critical that the public make their views known to Minister Roche before he makes this decision."
The Minister for Environment, Mr Roche, is due to make a decision on whether the route should go ahead as planned.
He will be considering reports on the significance of sites unearthed in test digs close to the historic hill before he decides if the National Roads Authority should be allowed to remove the objects for preservation.
The campaign group has warned it will take the case to the courts if the route goes ahead as planned and an excavation of the site is ordered.
People first inhabited the Tara-Skryne valley during the Stone Age and there are passage tombs on the site dating back to around 2,000BC. The site was considered the capital of Ireland, when it became the seat of the High King, who would rule the dozens of kingdoms that had emerged across the country.
Additional reporting by PA
