Hi Catherine,
There are 5 names of Margaret Brophy in Griffiths Valuation of Laois.
Boley Upper (Clonenagh) Mountrath
Dairyhill (Aghaboe) Borris-in-ossory
Ballynevin (Aghmacart) Mountrath
Harristown Rathdowney
Coolnamony upper (Rearymore) Clonaslee.
Perhape she in among these.
Around the time she was born, Castletown would have been a very small place, it still is, and records may have been slightly off.
Have a look at Griffiths.
Best wishes
Jack
