On
www.irishgenealogy.ie the following baptisms which may or may not be relevant to you
George Mahon baptised 8th July 1843. Dublin RC parish St Nicholas
James Mahon baptised 1837. Parish St Andrew
Bridget Mahon baptised 1852 Parish St Andrew
John Mahon baptised 1854 Parish St Andrew
Anne Mahon baptised 1856 Parish St Andrew
Michael Joseph Mahon baptised 1858 Parish St Andrew
Parents of above are Matthew Mahon & Catherine Torrney
There are 2 Baptisms listed for a Margaret Gibney.
1 28th April 1842. Parish St James. Parents Thomas & Mary Gibney
2 1848 Parish of St Andrew. Father Michael Gibney & Margaret
Cannot see any marriage for George Mahon Margaret Gibney in Dublin
Maybe they married in her home Parish.

hi am trying to find a marriage cert for a george mahon born in dublin in 1843 .he married a margaret gibney from kells in meath. have there sons birth cert he was born in 1869 in cole alley dublin south. i have tried g.r.o but no luck there ?