Question

William John McDonald born in Butler Co. PA 1815, who was his father?

Comments

Sorry to see this so late! Do you know in what part of Butler Co., Pa. that Willam lived? I have one in my tree born later than yours. He was born in 1859.

Answer 1

Based on this history of Butler County Pennsylvania, 1803: there appears to be two John McDonalds: one a Senior, one a Junior:

http://www.rootsweb.ancestry.com/~pabutler/1895/95x04.htm

As you propose a birth year of 1815 : I would suggest that the John McDonald Jr in this list may be the father?  Especially as in 1803 he was not listed as a single man: implying he was married.