My grandfather, James Francis Hillery born in County Clare in 1888 came throught Ellis Island before WW I. It was said that they spelled his name wrong and it should have been Hillary. My Grand father's sister's name was Della. She lived in Detroit, married and had no children.
My father, James Francis Hillery was the only son born in Detroit in 1925, moved to Grand Rapids MI in 1953. He told us that Sir Edmond Hillary was a 2nd cousin to him. Also, that his Father had siblings that left Ireland to live in South Africa and New Zeeland. (not confirmed: Someone in his family told me my Grandfather had a brother named Dennis who moved to Boston.)
My Grandmother was Mary Quinn born in 1889 in County Clare, Ireland. My grandparents met in the US and married here.
I have an aunt and some cousins who were close to my Grand Mother so I will get more info from them and write again.