The case for James O'Brien

FamilySearch. Luzerne County, PA Citizenship records. 28 Sep 1871.

While looking at the father of the branch of Pennsylvania O'Briens, James John O'Brien, several of the marriage records for his children list birth locations as Luzerne County, Pennsylvania. There's a James O'Brien who appears in the Luzerne County citizenship records in 1871, listing his arrival as November 1864 in New York. I cannot tell if this James was the same one who died in Pittsburgh in 1914. 

Michael Campbell served as a witness for James O'Brien on his petition for citizenship. I'm hoping I can find him in the 1870 US Census, perhaps living near the O'Brien family.

I have a hypothesis that James John O'Brien was the son of a James O'Brien, who may have been born in Ireland sometime about 1815-1825. This James may have been a son of my 3rd-great-grandfather John O'Brien, possibly from a first marriage before John arrived in the US and moved to LaSalle County, Illinois.