Thank you for sharing your information. It is interesting as it is the first I have heard of "John Donahue".
All of my 10 years of extensive research has only led to Hugh (Donaghy) Donahue. Hugh is from Tyrone County Ireland, emigrates from there in 1818.
My research has shown that Hugh's original name is Donaghy and most likely (not confirmed) as or Scots Irish origin. His original Irish name is more likely MacDonaghy, he changes it to Donahue because there were literate Donahue's (Robert) living near him.
May I ask what records or information you have that confirms John is Hugh's father? Is it only by word of mouth or do you have any documentation?
Please respond if you would to my email at firstname.lastname@example.org