Stone walls in Ireland are as old as farming, the oldest known to be those from Ireland's prehistoric farmers at the Ceide Fields in North Mayo which are approximately 6,000 years old.

Like any field enclosure they provide many uses: keeping cows and sheep in, keeping others out, delineating 'my land' from 'your land', but these stone walls also provide another useful function - they are dry built out of the local stone, in fact usually the stone from the very fields that they enclose. So by building the walls farmers are clearing the land.

And so the stone walls that one finds on travels in Ireland are local to that area. In County Down ( see image below) they are typically massive granite boulders, bigger than anywhere else and in Galway they are built of the abundant limestone.