Ellen Jane O'Sullivan from Kerry

Hello,  First thank you so much for your help in trying to break down one of my families Irish brick wall.  Someone in my family has been trying to do so since 1979 when one of my maternal aunts first put together a tree that goes back several generations.  For our O'Sullivan/Sullivan branch, she was only able to go back as far as my 2X Great Grandparents Ellen Jane O'Sullivan (born about 1838) and John D. Sullivan (born about 1839).  Since that original tree, one of my cousins has been able to go back to the mid-1600s on our French/German/Swiss side.  But no luck on the Irish branches.  

Several years ago I found Ellen Jane's death certificate, and we got a bit more information, her youngest daughter Anna indicated on Ellen's death certificate that her parents were Maurice O'Sullivan and (first name unknown) McHahan. 

Mainly I am in search of Ellen Jane and John D's birthplace.  I am not sure which parish they emigrated from in Ireland, but we do know they were from Kerry at some point. If I can find more information about other generations and maybe John's parents' name, that would be wonderful. 

Here is what we know about Ellen Jane and John D. 

John immigrated to the US in 1861 (per the 1900 US census)

Ellen Jane immigrated to the US in 1862 (per the 1900 US census) with a child named either Daniel or David (b 1861).  We are not sure which port either of them arrived in (New York, Boston, Philadelphia or via Canada).

The first time they appear in a US Census is the 1865 New York State Census in a small town in upstate New York, named Maryland. 

They eventually ended up in Pittsburgh, PA, by the time the 1880 US census was completed.   Between 1865 and 1880 they moved from Maryland, NY by way of Albany, NY, Sayers, PA; Athens, PA, and Somerset, PA.  According to some of the censuses, John D was a Stone Mason.  But by the 1900 census, he was listed as 'a day laborer.'  

Between 1863 and 1880 they had eight more children Ellen, Johanna Josephine, John Darrell, Honora, Maurice Francis, Eugene Francis, Mary and Kate (twins). Their last child was born after they arrive in Pittsburgh Anna.  

John D disappears after the 1900 US census. I have not found his death certificate. 

In the 1910 census, it lists a nephew John O'Sullivan living with Ellen Jane in Pittsburgh.  He arrived in 1906 via Philadephia and departed Ireland from Queenstown, Ireland on the Friesland. The passager list indicates he was from Dromin, Louth. He, unfortunately, died in Virginia on February 3, 1919. According to his death certificate, his fathers' name was Morris (I think it should be Maurice), O'Sullivan.  So my 3X Great Grandparents (Maurice O'Sullivan and (first name unknown) McHahan) had at least two children Maurice O'Sullivan & Ellen Jane O'Sullivan.  

Several years ago I did a DNA test with Ancestry I am approximately 45% Irish, right now Ancestry is saying it is highly probable that some of my Irish ancestors were originally from Munster. Specifically the Dingle Peninsula and North Central Clare.  Donegal is also mentioned, but I know one of my paternal great-grandparents was definitely from Donegal and the other was either from Donegal or Tyrone.  

That is all I have.  

Again thank you so much.  Any information anyone can give me would be greatly appreciated.   

Ellen Miller