Many Irish placenames are more-or-less phonetic renditions in English of the original Irish; there are a few commonly recurring words, such as Baile (town), Cnoc (hill), Átha (ford), Béal (mouth, as in river), Cill (church), Dún (fort), Lí(o)s (fairy fort), Droichead (bridge) and Gort (ploughed field). Thus you get Ballina, which is Béal an Átha, or the ford at the mouth of the river; Drogheda, or Droichead Átha, the bridge on the ford; Lismore, being Líos Mór, a large fairy fort, and so on. The further west you go, the more you seem to encounter an endless stream of Ballythis (Bally being the general anglicisation of Baile) or Knockthat (ditto for Cnoc). This is most likely due to the fact that the land to the west being poorer, the English tended to push the Irish in that direction whenever possible (for example, Cromwell's famous threat to the Irish was something along the lines of "Go to Connaught, or go to Hell") so that they could have the good land for themselves, and in that land new towns sprang up with more English names. However, nothing quite matches the further reaches of the west of Ireland, particularly the pockets where Irish is still the native language, and the immediate surrounds of those areas; it's almost as if there's competition to see how many of the "standard" words can be put into an anglicised town name. Thus, you won't be hard pressed to find something along the lines of "The town of the bridge over the mouth of the river by the ford of the fort on the hill of the ploughed field that used be a fairy fort but now has a church", which, by my reckoning, should come out as Ballydrogheadballinadoonknockgortliskill
If you get there, send me a postcard.
(For a more serious discussion on this topic, try IRISH LOCAL NAMES EXPLAINED
. Me, I'm just being a smartarse as usual.)