Obviously hugely important nowadays because the catchment areas for Schools are based on them.
The Department of Education are the ones who decide what the School catchment areas are. The Department doesn’t make its maps public but does say they are “based on” the Parish boundaries shown here. In practice there are very few differences.
The boundaries on our map come from (ongoing) work begun in Maynooth in 2009 and published by the CSO in 2011.
Contains Ordnance Survey Ireland data © OSi 2012