Earlier in the thread, Kathleenmary mentioned the following:
"Bridget Geraghty was born in Leitrim Village County Mayo. Perhaps Kitty was born here also.
There appears to be some family connection with the Tollett Family, who originally came up with Sir Arthur Shaen in the early 1700's. Rev John Tollett, as part of the protestant settlement was given lands in perpetuity.
Some family history (I am following this up) says that Bridget and Katherine were nieces of the Viscount of Mayo, Lord Francis Tollett of Moyrahan, and cousins of Lord William Tollett of Mayo 1780-1849."
That makes Katherine Geraghty the niece of Lord Francis Tollett. I don't know the exact source, but that wouldn't be impossible. Catholic and Protestant names aren't fixed in history. In any case, I thought the Tollett connection would be the next aspect to research thoroughly, then the specific details might reveal themselves. There might have been a village in Mayo named for Co. Leitrim - but it could be difficult to find. If it never existed, I suppose it would have to be Co. Leitrim, as you suggest? I've had trouble in the past trying to find townlands that no longer exist, in my research.
On the point about lifespan, it hasn't really changed, all that has changed is life expectancy. Rameses II (13th century BC) made it to 93 years, Eleanor of Aquitaine (12th century AD) made it to 82. If you had the means, and the general hygiene that entailed, you'd have a good shot at the 80s-90s. It's just that more of us are making it to that ceiling today. I noted that Major Bingham died in a "shooting accident", so he may well have made it farther had he taken it a bit more easy!