Sorry Mark, I have failed to pick up a John Patrick Stephenson, on the American census,with the little detail, you have given,
The only one I do find arrives 1879, and he is Irish,
He is a railroad worker,
living with his son Richard M Stephenson and family,
Pennsylvania, 1910,
The other is a miner living in 1892, at Green n Back St, Pittson Pennsylvania,
Then in 1918, you have a John P Stephenson, a railway gateman working for the Pacific Electric railway company,
would you like to post a confirmed census for us, America is such a huge place, I am possibly in the wrong area,
So before you try to go back to his roots , you need to have as much information as possible gathered in America, hearsay and family stories are not all ways accurate,