Catherine Donoghue (md. Hanratty)

I have been hot on the trail of my 4th Great-Grandmother, Catherine Donoghue, for years.  She is my immigrant ancestor on my direct maternal line and I know by her death certificate that she was born in 1833 in County Kerry, Ireland and probably immigrated around 1845 at 12 years old.  She died in 1897 in Algiers, New Orleans, Louisiana, USA.  She married Francis "Frank" Hanratty (b. New York).  I am positive that Donoghue is her maiden name due to the fact she was married to Frank and had her first child at 18.  There are only two baptismal records I have found (on Ancestry) for a Catherine Donoghue b. 1833 in Ireland....one whose mother's maiden is Cullotty and one whose mother's maiden name is Cournane.  I know that Cournane and Courtney are rather interchangable in Ireland.  Out of the 6 dna match lists of close family members and myself, there are no Cullotty matches nor matches with Cullotty in their trees.  However, though there are no Cournane matches, every one of us have matches with the surname Cournane in their family tree's.  I am leaning toward that being my Catherine...but have nothing else to really verify.  I would appreciate any help or information that may help me to find out who my Catherine's family in Ireland is and where in County Kerry they came from.  Thanks!