Ice age people did not existed in Ireland, as was maintained of both Ireland and the American continent until fairly recently, and they have not left any evidence of their passing. Yet the presence of Ice age people is no longer in dispute in the Americas especially below the southern edge of the Ice floes where their artifacts have not been ground to dust. North of the Ice line artifacts have still not been found, yet the existence of people in this environ is certain because the continent was colonised from north to south. Perhaps an Ice age people did exist in Ireland also but if so their artifacts have almost certainly long ago disappeared since ice covered most of the island at one time or other and so evidence of these folk cannot reasonably be expected to have survived in any abundance. The Island did sport a wildlife at this time and where there is food there are invariably people to eat it. The incongruous discovery in 1860 of a horse along with mammoth, bear and hare in Shandon cave near Dungarvan are of great antiquity but the species found at this location are all cold weather types with the exception it seems to me of the horse. Why would an animal which today generally favors clement climate be found with such a hardy bunch of beasts unless it was brought there by humans?. When did people first domesticate the horse?. The animal in question is at least 40.000 years old which seems to me to be way too early for domestication and may have lived during some brief and obscure interglacial period from about 100.000 to 75.000 years ago.. Time will tell if the so called "Clovis barrier" can be pushed back in Ireland as it has been in the Americas. However to date it looks certain the island was not inhabited prior to the current interglacial as surely some solid evidence would have surfaced by now.
The earliest known human sites in Ireland are almost 9000 years old and littered with thousands of stone edges, mostly microliths, one to two inches in length and a few core type axe heads. These microliths were set into wood in rows to produce a longer and consequently more effective cutting edge. Nobody knows who these people were but they were obviously of the hunter/gatherer type and ranged through much of the northeast, albeit sparcely distributed in other areas. Evidence of these people has been found near Coleraine, Dundalk, the Shannon basin at Boora Co Offaly and as far south as the Blackwater. What happened to these people is still a bit of a mystery as their implements disappeared from the archeological record 8000 years ago in a very short period of time. Perhaps they emigrated to America like so many of their progeny :-} or simply changed their manner of working as more material resources were discovered. Soft hammer techniques were used to produce these tools and it just does not make sense to me that these working methods and the tools they produced should have disappeared so quickly and completely. Hopefully archeologists will in the future be able to sort out this question for the rest of us.
The next significant technology of note starts about 8000 years ago and is characterized by a more robust implement than the microlithic technology preceding it. This goes against the normal course of development as stone age implements generally tended to become more refined and delicate as time progressed. The most extensive site of these new people is centered around Larne and the technology is often referred to as Larnian even though their technology is widely distributed in time and space. Indeed the workings at Larne may represent a kind of factory setup from which material was distributed island wide over time as the abundance of suitable material in the locality might have encouraged such a situation. Still its easy to jump to conclusions like this and the reality is often far more complex than can possibly be imagined today.
Until recent times the product of stone age culture was viewed by Irish country people as the weapon of "Na Sidhe", or Fairie and sometimes referred to as "Elfdarts". If a piece such as an arrowhead was found in a field with sick animals it was seen as the cause of the illness. A cure was effected by placing the artifact in the animal's drinking trough.