Francis, I don't know if you have contacted anyone in Cavan about Crosserlough records, yet. I contacted the Hetitage Center and found out that no records are on file anywhere prior to 1843 for this Parish. I had hope for an 1850's marriage record but no luck there either. Have you found the 1821 Census of Crosserlough at Rootsweb? If you put Cavan into the search engine the website should come up, there are quite a few Galligan families on that. I don't really have a connection to the Galligan families, yet. A Katherine was mentioned in my Aunt Susan Mulvaney Brady's Obit from NYC. I think the people from this area stayed in a tight circle where ever they immigrated to.