I have been able to track down my greatgrandparents in the 1901 census, and it states he was from Cty Monaghan. Any help would be greatly appreciated!
http://www.census.nationalarchives.ie/pages/1901/Antrim/Malone/Dunmurry_Town__part_of_/997746/
I found three different civil birth index records in Co. Monaghan for a Hugh Keenan from 1866-1868 which ties to his reported age of 34 in the 1901 census. However, without knowing his parents names (or at least one name) makes it difficult to pinpoint the correct birth record. The GRO www.groireland.ie can provide a copy of a registered birth for around 4 euros. You need to fill out their form and provide the year, registration district and the volume and page numbers. Hopefully, you can find more identifying information.
Roger McDonnell
First Name: Hugh
First Name: Hugh
First Name: Hugh
Based on the dates of the census, and his ages listed, I am rather sure that he was born in 66
By any chance, did any of these have a father named Hugh as well? A possible marriage registration was found for a Hugh and Mary, with the father named Hugh as well.
The index records don't show the names of the parents. You have to obtain the actual record.
Roger