I found 2 probate records on PRONI. The first was issued in 1946.  The District Registry was Londonderry.    Does anyone know the boundaries of that Registry for 1946?  I've tried Google but no luck. The second was issued in 1951.  The District Registry was Belfast.     Does anyone know the boundaries for Belfast? I apologize for being vague but the recipients might be still alive.  Thanks in advance,Ellen