Hello Frances,
My name is Lance Fallin and I have the same problem that you have but with a different "Fallin" (the surname Fallon has been spelled many ways, it's not really an English language name so, it gets spelled differently among English speakers... for centuries).
As far as I know Fallon, McFallon, O'Fallon etc all come from County Roscommon originally, however before then ... they might have been elsewhere in Ireland. There seems to be a connection with the Kelly and O'Neill or O'Niall families ... but that is going so far back into ancient times that I am not willing to "deal" with THAT history right now.
My focus has been simply to trace my ancestry as far back as I could, ultimately getting back to Europe (principally Ireland mind you), and bearing that in mind it seems that we have 3 main branches of "Fallin" families in the USA (from mid-atlantic and southern states anyway).
1. Dorchester County, Maryland 1600s and 1700s Darby Fallin and Redmond Fallin etc
2. Charles Fallin of Northumberland County, Virginia (1600s)
3. (a) Teague O'Fallon of Lancaster County, Virginia (1600s)
3.(b) Redmond Fallon of Pittsylvania County, Virginia (a county which was formed from Halifax and Lunenburg Counties).
(I believe that Redmond Fallon of Pittsylvania County is a grandson of Teague O'Fallon of Lancaster county, but this is just a hunch for now)
On a genealogy blog site about the "Fallin" family, that I have been a member of for several years, some of us took a YDNA test and it was found that some descendants ... direct male line descendants of Charles Fallin of Northumberland although had the name "Fallin" they genetically trace back to Falen and Whalen (O'Faolain) (Oh Fway Lin) and not to the O'Fallon's of Clann Uadach (Roscommon). The Fallin Family of Northumberland County Virginia therefore traces back to the Desies ... I forget which county or counties, but it is towards the coast and it would be south and east of County Roscommon... towards the SouthEast Coast of Ireland (but not as far south as Cork. Basically ... down the road south of Dublin a ways.
We now have to get some of the Maryland "Fallin" descendants to do the dna testing and see if they match up with my Virginia "Fallon", "O'Fallon" and "Fallin" ancestors.
Also, be on the lookout for name changes and spelling differences: I've seen (just in American archives ... Fallin, Fallon, Fallen, Falling, Falden, Fallan, O'Fallon, O'Fallin etc etc
I'm convinced that once we get back to the 1600s .. as the above mentioned "Teague O'Fallon"
He was arriving by 1656 in Lancaster County, Virginia. I think he was about 14 years old and alone.
I believe he was part of the fallout of the Cromwell era ... a lot of loss of life and property back then, and kids were basically sent away or sold off or just gathered up by force and sent almost as slaves to the "New World", many were first sent to Barbados and St Kitts and Nevis islands in the caribbean.
My point is ... I think DNA is the only way for those of us who trace back to the early 1700s and 1600s, but I'd never give up on the paper trail either. It's definitely a challenge.
Best of luck to you,
Lance Fallin (who is slowly learning Irish language by the way)
Sl?n,
Labhr?s ? Fallamhain (I just like to see my name in Irish)