I'm from Leitrim, two of my Great grand mothers were Rooney. One was from Glenade which is in the civil parish of Rossinver.
My mother is from Mullies which is in Killasnet Parish, but where she is from is on the shore of Glenade lake so we always referred to it as Glenade (Even though it was Mullies)
Anyway, There is a great site with the 1901 census for Co Leitrim: http://www.leitrim-roscommon.com/1901census/census.shtmlhttp://www.leitrim-roscommon.com/1901census/census.shtml I did a search for Rooney in Rossinver (Can't narrow it down to Glenade unfortunately) there are 61 Rooney families however there are no 5 year old Partrick Rooneys or 4 or 6 year olds.
I did the same search for Killasnet and found the following: Information in order of: Townland Parish Barony County Description Head of household Surname Head of household Given Head of household Occupation Other occupants (First named after head of household is spouse unless otherwise stated):
If you're sure about the DOB of your Grandfather I reckon one of the above is yours, I was watching out for 4 and 6 year olds as well, I can find out if Tomrud or Largy townlands are near Glenade lake from my mother.