It’s great to hear that you are tracing your Irish Family History and have had some success so far!
Before 1864 records were kept in the form of church and parish records; while some of these have regrettably been lost over the years, all the surviving records have been sorted into county-based genealogical centres. For County Roscommon, you may wish to take a look at Roscommon Roots
to see if they are able to help you with your research. Irish Geneology is also a good place to find records, they have several different search categories, one of which is migration records
to see if you can find the detail for Andrew, James, Margaret, and Susan. We have a general resources page on our website that has lots of links to genealogy resource places that may be of interest too.
In 1864 civil registration was introduced in Ireland, which is when we started seeing the formal registration of births, marriages, adoptions and deaths. These records have been kept at the General Register Office of Ireland
(GRO), to this day. Do you have records on where Anne and Patrick lived during their marriage? Did they remain in Roscommon?
I'm sure our Industry partners and fellow members will have some advice also.
We hope this helps.