Well, it took awhile--but found the missing sisters!
There was one sister who never left Ireland, Sabina "Sibby" Berry, who married Michael Conway in 1862. She died in 1873.
But what about those mysterious 3 other sisters mentioned in Michael Berry's 1903 obituary?
Just recently a cousin was looking at dna matches and found a link to Sarah Berry who married Thomas Kirby. Sarah died in 1916 in Peru, LaSalle County, Illinois and is buried in the same cemetery as Michael Berry, but her obituary and death record didn't give any helpful info.
While navigating thru the cemetery on findagrave another Berry maiden name appeared, this for an Ann (Berry) O'Dowd who died in 1911. Info from her death record was on her memorial--and it said her parents were Anthony Berry and Sarah Kane. This was slightly confusing, because Joanna Cicely Fennell, a professional genealogist in Ireland, had found a record for a likely sister Ann Berry marrying Michael Fleming in 1849 and having two children. But he married again in 1855, so it was presumed Ann died before then.
A local friend got Ann (Berry) O'Dowd's obituary--and this time struck gold!
It listed all six sisters who came to the US:
Mrs Michael Prendergast (Bridget)
Mrs Patrick Mohan (Catherine)
Mrs James Walsh (Margaret)
Mrs Thomas Kirby (Sarah)
Mrs James Trench (Sallie)
And of course Ann, Mrs Patrick O'Dowd
Also listed was a daughter, Mrs Thomas O'Dea (Mary Ann), one of Ann's children with Michael Fleming.
Ann's second marriage, to Patrick O'Dowd, took place on 21 May 1854 at the Old Cathedral (The Cathedral of Saint Louis) in St Louis, Missouri. She is listed under her maiden name, the daughter of Anthony Berry & Sarah Kane, but no mention of her previous marriage. (None on Michael Fleming's second marriage record in Ireland the next year either.)
The siblings are linked on findagrave thru their mother Sarah (Keane) Berry, Find a Grave Memorial 235755256. They are also on the FamilySearch tree and on my Ancestry tree, Steph's 99%.
