I'm really going to have to get to Manorhamilton some time.
It seems to me that to crack the Leitrim branch of the Algeos, I need to get information on land-holding, and further back than the online edition of the Landed Estates database takes one. I know that Lewis ALgeo was born about 1760, married about 1787, died around 1810, and held Glenboy during the latter part of that time. Presumably a near relative, Robert Algeo, owned Hollymount, an estate which is very near to Glenboy -- he was born in 1743, died in 1823, and held Hollymount for much of that time. When did he and Lewis arrive in Leitrim? I am thinking that land-holding records could hold part of the answer, but just don't know what is available that far back, or how to go about locating them (or anyone who has access to said records).