Dennis and Hannah are my GGG Grandparents on my maternal side. According to the family history put together by my Aunt Laura McCoy we have the following:
Patrick (b. 1799), Dennis (b. 1804), James (b. 1813), Anthony (b. 1816) are the brothers. John (b. 1811) we believe is a cousin. A 1870 Census has a Patrick McCoy 6/12(son of James McCoy) staying with his uncle Patrick. Determining how John McCoy connects to the family has been a difficult task.
Dennis and Hannah had 9 children: James Thomas (b. 1845), Anthony (b. 1847), Sarah Frances (b. 1850), Joseph (b. 1853), Mary Ann (b. 1854), Elizabeth Jane (b. 1858), Daniel (b. 1860), Julia (or Julie) (b. 1863), and Catherine (b. 1865). Our records have James and Anthony born in Ireland, Sarah in Penn. and the rest in Iowa.
My line extends from their son Anthony who married Emily Harlan. They had 8 children. Their son Albert married Sarah Rose Duffy.
Albert and Sarah's son Lawrence married Mildred Alice Burns. Lawrence and Mildred's daughter Mary Ann is my mother.
Anyway, I just wanted to write and say hello. It is always fun to find someone who is looking for the same people as you are. Our family history file is constantly being updated as we find new records and identify false members. (I once added in 15 incorrect people because I picked the wrong census file!) Good luck with your family research.