I'm wondering if this could the widow of Jeremiah O'Connor and their children:
http://www.census.nationalarchives.ie/pages/1901/Kerry/Kiltallagh/Lisna…
If you go to the Irish Genealogy site, you can find the Lisnanoul baptism transcriptions for the chidren. They match up to the parents Jeremiah O'Connor and Ellen Mahony. Since Jeremiah would have been 36 in 1901(versus Ellen at 42), it could possibly be a second Jeremiah. Here's the link:
http://churchrecords.irishgenealogy.ie/churchrecords/search.jsp?name2fm…
By 1911, it seems that Ellen Mahony O'Connor also died:
http://www.census.nationalarchives.ie/pages/1911/Kerry/Kiltallagh/Lisna…
Also this transcription could be for the marriage of John and Mary Teahan. It says she is from Ballyfinane.
http://churchrecords.irishgenealogy.ie/churchrecords/details/a5d95f0532…
There were three Teahan families in Ballyfinane at the 1901 census. There were a few Mary Teahan's born in Ballyfinane in the 1820's. The one whose father is named Dermot could possibly be yours. Her second son was named Jeremiah which is a variation of Dermot. Typically the irish named their second born son after the wife's father. I'd be totally convinced if the second daughter was named Mary.
http://churchrecords.irishgenealogy.ie/churchrecords/details/1136100146…
You should find some more clues if you do some more searches on the National Archives and the Church record site.
Cathy
Chicago IL