Trying to locate records of my grandmother's siter

My grandmother's youngets sister, Johanna Moore, was an unknown person to my current relatives in County Laois.  Johanna grew up on the family farm in Borohan, Errill, Co Laois.  Errill does not yet have a parish page and since the farm is on the road between the two towns I am posting on the Rathdowney parish page.  The last record I can find of Johanna is the 1911 census, at which time she was still on the family farm.   She is not buried in the family plot in the cemetary in Errill.  A guess could be that she married and moved from the family farm, but I cannot find a record of that either.  I would greatly appreciate any ideas or suggestions that others have as to what else I can do to find out what happened to her to solve this family mystery.  Thank you.