Thank you for that information. It is interesting to note that there two Creegan births prior to 1830 in Drogheda. However, if you look at the family listing I posted yesterday, you will see I have a POSSIBLE marriage between a Michael and an Elizabeth with a son William, born 15 March 1828 in Drumshallon (6 Irish miles to the north of Drogheda). Somehow, I was sent this information from Ireland and it seems as though it might fit with this family. My John Creegan was born in 1830 and he was supposed to have had a twin. Your information may reflect this family. Certainly, it is not unreasonable for John to have had brothers born 1820 and 1823. Family legend has it that there was no-one left in Ireland from this family after 1854, so the later Creegans may have been cousins. There is certainly no Richard appearing in the names of John Creegan's children.
I live in Canberra Australia, so telephones would be largely impractical because of cost and time difference. I am happy to continue this conversation off Genforum if you wish.