Children:
Ellen 1869
Sarah Ann 1866
Peter 1870
and Mary Ann also? When was she born?
Have you found baptisms for these children? Baptisms can be invaluable as they provide the names of the godparents, who are often relatives (as I have stated above).
Also, I am looking for the McKennas, not the Donnelly’s. About Patrick
I understand that, but you need to know everything you can about Eleanor, including the names of all her children, and information about her siblings,
before you go back to her father. How could you know that you are researching the correct Patrick McKenna, if you have no other context?
You state that:
My oldest ancestor is Patrick McKenna (Farmer), he was born circa 1810 in Aghaloo or Errigal Truagh. He married circa 1835 in either Aghaloo or Errigal Truagh. He had a daughter named Eleanor about 1841 (death age extracted from 1901, her death date).
But you don't offer any sources for this, so I am trying to take a step back to establish what sources are available and what they tell us. I suggested that Eleanor may have been the daughter of a Patrick and Bridget McKenna in Errigal Truagh, but I wanted to try and provide confirmation of this by using the names of Eleanor's children and trying to find the names of Eleanor's known siblings to see if Patrick and Bridget had baptised children with these names. For example, Eleanor's marriage was witnessed by a William, this could suggest that she had a sibling called William. However, she had no daughter called Bridget, which may be expected if her mother had been Bridget. Essentially, trying to find more records to establish links between her and other McKennas in the area. I can see that there was certainly more than 1 Patrick McKenna in the area at the time of Eleanor's birth.
