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Marriage records for the RC parish of Killedan (Kiltimagh) start in 1834 but unfortunately, baptismal records start in 1861. I searched on the subscription site Roots Ireland and found an 1845 marriage record for John Lavin and Bridget Gill. See transcription below. I searched for records for children of John and Bridget and located three. Likely Catherine was one of the older children and baptized pre-1861 so records are not available. Michael Lavin was baptized in April 1863 See below. Civil registration started in 1864 and I located the civil birth records for the two youngest children.Bryan in 1862 and Owen in 1872.
I located the November 22 1884 marriage record for Martin Lavin and Margaret Carroll. The names of their father were shown: John Lavin (alive) and Martin Carroll (alive). There were at keast 12 children. Martin died September 11, 1906 at age 52 https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1907/05519/4546970.pdf
Here is the 1911 census for Margaret and family http://www.census.nationalarchives.ie/reels/nai003019485/
I found an 87 year old Margaret Lavin who died in Cordarragh in 1954 possibly this is the widow of Martin. https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1955/04429/4156887.pdf
Date of Marriage:24-Mar-1845
Parish / District:Killedan RC parish
Name:Michael LavinDate of Birth:
Date of Baptism:25-Apr-1863Address:GurtgarriffParish/District:Killedan RC parishGender:MaleCountyCo. MayoDenomination:Roman Catholic
Father:John LavinMother:Bridget GillOccupation:
Sponsor 1 /
Informant 1:Pat LavinSponsor 2 /
Informant 2:M. Amie Lavin
Civil record for Bryan eighth record on page https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1865/03569/2315189.pdf
Civil record for Owen last record on page https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1872/03244/2188770.pdf