A flint axe found in County Waterford similar to this one may be the oldest Irish artifact ever.
[2:3] Flint flake, Mell, Co. Louth.
Palaeolithic, 400,000–300,000 bc.
The Mell flake is a heavy trapezoidal flint flake with a width greater than its breadth. When striking produces a flint flake, a distinctive convex area known as a bulb of percussion is produced immediately below the point of impact. This feature is present on the Mell flake demonstrating that it was fashioned by human hands. It is not a tool but a piece of knapper’s waste that is most closely comparable with the lithic products of the Clactonian and Acheulian cultures of southern Britain. These stone-working industries are associated with the activities of early hominids and the Mell flake could date as early as 400,000 bc. It was probably fashioned on land that now forms the basin of the Irish Sea where an advancing ice sheet picked it up. When the ice retreated melt-water deposited it near the Irish coast in gravel. 1972:65. L. 8.5 cm; W. 6.0 cm.
Mitchell & Sieveking 1972, 174–7.