I found Thomas! But need more proof. 1880 Census North Cambridge, Cambridge Mass. Pg 304A
Thomas P. Brosnahan Age 38 Ireland M&F Ire. Clerk RR ( b. abt. 1842) ( My gg grandmother Hannah's brother)
Hannah wife Age 36 b. Ire. ( maiden name unk) b. abt. 1844)
Ellen ( Nellie) Age 12 ( b. abt. 1868) MA
Patrick Age 10 ( b. abt. 1870) MA
John Age 8 ( b. abt. 1872) MA
Hannah Abe 6 ( b. abt. 1874) MA
Thomas Age 4 ( b. ab.t 1876) MA
Mary Age 2 ( b. abt. 1878) MA

The above Patrick, son of Thomas P. had a daughter Irene. There is an Irene Brosnahan listed in the SSI for Cambridge MA
Born July 9, 1911 and died Nov. 17, 1995.

Hoping someone will see this who is researching the same family, or in the same area, that would be willing to help me with further identification of the above family. I have extensive information on these Brosnahans from Castleisland Co.Kerry.