I too am descended from a Patrick Keleher.I'm beginning to think that the name Patrick Keleher is the Irish equavalent of "John Smith"!"our" Patrick Keleher was Patrick Dennis Keleher, b. in Ireland in abt 1813 and died at age 37 of a fever in 1849 in Georgia.He was in Georgia by 1841.Likely he came to Georgia to work building a railroad, (likely betwee 1838 and 1840) but he bought land (in 1841) and settled.
I can eleminate most of the (seemingly!) dozens of Patrick Kelehers as they immigrated later.I did find one Keleher family in Canada with very similiar naming patterns and who migrated before 1840.Do you have dates?
I have no idea where in Ireland he came from.Family legend has it that he came with his brother and I believe his name was Michael.