Wow, the house in Mohill is quite a pile! www.loughrynn.ie
You probably know all this but while I was searching for Estate Records came across this history. In 2006 house turned into a luxury hotel Lough Rynn Castle Hotel.

www.landedestates.ie

The Civil Parish is Cloone, Townland Clooncohin/Rinn. The Clement family owned to the 1970's and the holdings for the Clements was about 50,000. acres in Galway and Donegal, one of them who was Justice of the Peace for Leitrim was born in Dublin originally and then murdered in 1878. He was one of the most hated landlords by both RC and Protestant tenants. There are several books about the family history.

www.loughrynn.net also has some amazing history of the estate although have been unable to find where the estate household records reside. Rental Notices & agreements are at the National Library in Dublin.
www.nli.ie/pdfs/mss
Collection No. 99
Mss 32, 639-81
Mss 33, 814-33-33, 889

Trade Directory 1931, no Robert Thornton, lots of licensed premises in Mohill. Perhaps he just worked at a pub.
The only Jane Robinson birth was I believe much too old, 1868 Leitrim and Robert Thornton 1905. The genealogy websites usually only have records to 1900. Although you can find many people on the website www.familysearch.org up to the 1950's.

www.nationalarchives.ie

Too many Jane Robinson's and not knowing her age made it difficult, but I would assume to be about 1903.

1911: Perhaps related? Father?

Robert James Thornton #10 Rinn Leitrim age 38 Painter
wife Elizabeth 40
John Henry 14
Alfred 12
William 10
Thomas 5
Kate 3
Herbert 1

Try the Leitrim Library as they may also have Estate records under 'local studies'. Certainly you could email them and ask where the estate records for household staff might be archived.

You could try the telephone directory for Leitrim which is online and look for the surname Thornton & Robinson's in the Mohill area.

There is some requests to the government in Dublin to release the 1921 Census early, it would be under the 100 year law for census but they are being encouraged to do this for genealogy purchases.

www.mohill.com you can take a google walk through town
has links for genealogy and finding family.

www.familysearch.org has the marriage record for this couple April-June 1923 Mohill LDS vol.3 Pg. 137 #4199367
This is the LDS microfilm and it can been seen at any of the LDS Heritage Centers near you.
www.groireland.ie if you haven't already you should be able to get a copy of the marriage certificate with the year listed above. Only names would be the couple's father's names, place/parish, Mohill is the Registration District, and perhaps witnesses.

A birth record should have father, mother's name and maiden name, place/parish and perhaps godparents?

Robert Thornton civil birth registration Oct-Dec 1905
Mohill, LDS Vol.3 Pg. 168 #4193984

Elizabeth Jane Robinson civil birth registration Oct-Dec 1901, Manorhamilton LDS Vol.2 Pg. 190 #4193982

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