Through two newspaper articles, a will, and the full passenger list of the Roscuis ship in 1845, I have found that Catherine came to America with her sister, Elizabeth Donoghue. They were 12 and 13 respectively. I have been able to trace Elizabeth's family in America as well which lines up with what info I've recently discovered, but cannot figure out who they are in Ireland. The four or so families that I thought lined up with possibilities for Catherine, do not include a sister named Elizabeth. Of course, I know that sometimes first and middle names are used interchangeably. There seems to be another Elizabeth Donoghue (spelled incorrectly as Donnohow) age 60 (abt. 1790 birth) living with Elizabeth and her husband's family in the 1850 US Census. There is also an Ellen Donohue, age 16, listed as a servant from Ireland in that same census in their household... so maybe a niece or cousin? I did find an Eliza Donohue who sailed from Ireland on the ship Wisconsin on 23 August 1848 through Liverpool to arrive in New York and stay in the USA with a birth year of 1788. I'm wondering if this is the "Elizabeth Donnohow" listed on that 1850 Census.
If any of these names and details sound familiar, please reach out to me! Even through DNA and mtDNA, I have had no luck finding my family in Ireland.