Isaiah McNees was born in Copte Hill, County of Cavan, Ireland in 1752. I looked it up and Copte Hill is a real place. That made me happy. This is one of those things I am unsure of because I haven't really looked at Ireland to know if places are right or wrong.
He arrived in Philadelphia, Pennsylvania in 1736 at the age of 16. This is where it all goes wrong. I was going to delete the whole post but decided to leave it in all it's misinformation so I know to go back and do the real research needed.
The source document on Ancestry.com is the "Pennsylvania, Quaker arrivals at Philadelphia (Meeting), 1862-1750". I consider this a valid source as the Quakers kept detailed records of who was a part of their meetings but it does muddy the waters. If Isaiah arrived in 1736, based on his birth year, he would have been 16. However, the meeting notes dated 21 Feb 1736 says:
"who hath lived within the compass of our meeting these Twenty years." He is about to "remove from hence with some of his Children (he being a Widower) to Pensylvania."
I have him married to Elizabeth with four children who were born after he arrived in America. So either the meeting note is incorrect or this piece of record belongs to another Isaiah McNees.
Rats, back to the drawing board.