Jan:
Welcome to Ireland Reaching Out!
Mullingar is a townland in Donaghmore civil parish which is on the border with Co. Tyrone.
I searched Roots Ireland and found an 1866 civil birth record for a Catherine Boyce with father Francis and mother Grace McBride. The townland was shown as Dooey. There are two Dooey townlands: One in Glencolumbkille civil parish and the other in Lettermacaward civil parish. Neither parish is near Donaghmore so I'm confused.
Cathereine had at least three younger siblings that I could locate: Anne 1870 Patrick 1872 Mary 1875. The 1875 record showed Douay which I presume is Dooey.
Let me know what questions you have.
Roger McDonnell
Name:Catharine BoyceDate of Birth:22-Apr-1866
Registration Date:29-Apr-1866Address:DooeyParish/District:ROSGUILLGender:FemaleCountyCo. Donegal
Denomination:Civil Record
Father:Francis BoyceMother:Grace McBride