So in terms of relocating to Lafayette County, Missouri, the movement could have been in direct result of the Potato Famine, or in later years by the opportunity seen through letters home by those that did make the trip earlier. As I've read in places that one draw is that certain groups from locations in Ireland would tend to move to areas of the U.S. that held earlier immigrants of their locale. Can't say that I've been able to establish that for Lafayette County, but then I'm just starting. Maybe that puzzle will come into place eventually.
Where I put my stake in the ground is an 1860 marriage:
Immaculate Conception Catholic Church Records, Lexington, Missouri
married: Aug 1, 1860
James Hughes s/o James Hughes and Bridget Quigley
to: Sarah Hastings d/o Michael Hastings and Bridget Stuart
witness: John Hughes and Bridget Moran / Edward Hamill / 7.50
So my first question... is John Hughes kin to my James Hughes, or is it a common name enough to just be a coincidence? And how is Bridget Moran related, possibly to Sarah? There my guess it that yes, she may be fellow County Mayo countryman, but to date I haven't figured that out. Other than I see quite a few references to common surnames to County Mayo as being Moran.