Let me draw your attention to this wonderful resource provided by the Ordnance Survey of Ireland. It is an online map viewer that allows you to superimpose images from certain historical maps of Ireland onto the present day map series. You can also view just the up-to-date map or just the historical maps as well.
It is of special interest to potential house buyers. For instance, we were interested in a certain house and had scheduled a viewing (that was cancelled due to a burst pipe). But the house has a slight tilt and we were concerned about the possibility of subsidence. Well, it turns out that if you locate the house on the OSI map viewer and then overlay an image from one of the historical maps, so can see that the area where the house is was called Poor Man’s Well and it looks like there was a pond once at that very spot.