Ireland is, I think, somewhat unique in that it has geographical units called "townlands". There are over 60,000 of them! You can find out more at https://en.wikipedia.org/wiki/Townland
The problem so far as FamilySearch is concerned is that most townlands show up as being invalid when trying to put in someone's place of residence. Let me give you an example. My wife comes from a townland called "Cullane" which is in County Mayo, not far from the town of Swinford (FamilySearch only accepts the old spelling of "Swineford" by the way). Her father's name is Patrick Gallagher. In the 1901 census there were 170 people of that name in County Mayo, over 20 of whom were from "Swineford". You can see the difficulty that this causes in trying to find the right person. (Incidentally, there are 3,353 Gallaghers in the county in the same census). In our case, because FamilySearch is collaborative, this often causes frustration with more than one Gallagher ending up in the wrong family.
So - can something be done about this?
Another issue relates to a county which is often called by two different names - Derry or Londonderry. It may seem petty - and people can sometimes be a bit precious about it - but there are historical and cultural reasons for this. FamilySearch only allows "Londonderry". I think it would be straightforward to permit either option.