This is not a monument in the conventional sense, no carved stone or ceremonial structure, but a working place, a valley where people came to make axes from roughly 3800 BC onwards, leaving behind the full physical record of a craft industry that ran from raw extraction to finished tool.

Excavations in a valley running northwest to southeast, beside an upland area of Lambay Island, uncovered every stage of axe production. The stone being worked was porphyry, a fine-grained igneous rock, and the debris left behind, known as debitage, the waste flakes and fragments shed during knapping and shaping, was found alongside the tools used to produce the axes. Large cobbles of conglomerate and granite were used to break material from the outcrop, while smaller hammerstones were employed in the roughing-out stage, shaping the raw blanks into something closer to a finished form. Rubbers, used to grind and polish the axes to their final edge, were also recovered, as was struck flint and Neolithic pottery. The site, known as the Eagle's Nest, holds a particular distinction recorded by archaeologist Gabriel Cooney: it is the first quarry site identified in either Ireland or Britain where hammering and pecking, rather than flaking, was the primary technique used to work the stone. That finding places Lambay in a specific and largely unrecognised position in the prehistory of these islands.

Lambay Island is privately owned and access is not straightforward; visitors require permission from the estate, and the island is not served by any regular ferry. Those who do make it across will find a working farm and a landscape that has changed relatively little over centuries. The archaeological valley itself is not a managed visitor site, so anyone with a genuine research or heritage interest would be better placed approaching access through formal channels. The finds from the excavations, rather than anything visible on the ground today, carry the weight of what makes this place significant.