Diane,
Thanks for all the additional information which is helpful.
It appears as if your husband is probably related to the author J. P. Donleavy, as both are descended from the Killasona Townland, Granard RC Parish, County Longford Dunleavys/Donleavys.
J. P. Donleavy (1926 - 2017) was the son of Patrick John Dunleavy, a native of Killasona Townland in Granard Parish, County Longford. His first novel "The Ginger Man" was published in 1955. He lived at Levington Park, just outside Mullingar, County Westmeath.
https://en.wikipedia.org/wiki/J._P._Donleavy
According to James P. Farrell’s Historical Notes of County Longford and Edward MacLysaght’s Irish Families, the Leavys were one of the clans/septs holding territory in County Longford circa 1550. Leavy is an abbreviation of the Dunleavy/Donleavy surname.
Have a look at the following website in relation to the Donlevy surname:
https://en.wikipedia.org/wiki/Donlevy
In particular, I note that 'Some MacDonlevys in Donegal adopted the surname Mac an Ultaigh, meaning "son of the Ulsterman". Also, Uladh is the Gaelic for Ulster, a province in the northern part of Ireland, containing County Donegal and eight other counties.
I see the following records in relation to the Donleavy/Dunleavy Family of Killasona Townland, Granard Parish, County Longford:
Granard Graveyard, County Longford - Plot No. 279, Section C
Michael Dunleavy, Killasona, died February 1966, aged 68
https://www.irishgraveyards.ie/plot.php?plotno=279&yardid=155§ion=C
1911 Census - Killasona Townland, Firry District Electoral Division, County Longford:
James Dunleavy (60) & wife Bridget Dunleavy (50) and their children:
Patrick (20), Mary Kate (18), Thomas (17), Michael (13), Bridget (11), John (10), Lizzie (6) & Rose Anne (5)
All RC and all born in County Longford
http://www.census.nationalarchives.ie/reels/nai002891325/
1901 Census - Killasona Townland, Firry District Electoral Division, County Longford:
James Dunleavy (49) & wife Bridget Dunleavy (38) and their children:
Christopher (15), Matthew (14), James (12), Joseph (11), Patrick (10), Mary Kate (9), Thomas (8), Anne Maria (7), Michael (5), Bridget (3) & John (4 months)
All RC and all born in County Longford
http://www.census.nationalarchives.ie/reels/nai001025989/
Death Certificate, 28 February 1896, Killasona
Mary Dunleavy, female, widow, aged 75, widow of farmer Christopher Dunleavy, old age - infirmity - no medical attendant
Informant: James Dunleavy - son of deceased - Killasona - present at death
Registered 25 March 1896 by Eugene Doherty, Registrar
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1896/05906/4675979.pdf
Marriage Certificate, 15 February1885, Granard RC Parish, County Longford by Rev. Eugene O'Reilly, Catholic Curate
James Dunleavy/Donleavy, full age, bachelor, farmer, Killasona, son of Christopher Dunleavy (dead), farmer
Bridget Connell, full age, spinster, -, Killasona, daughter of Matthew Connell (alive), farmer
witnesses: Joseph Donleavy & Lizzie Connell
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1885/10860/5965515.pdf
Death Certificate, 1 December 1875, Killasona
Christopher Donleavy, male, married, aged 63, farmer, bronchitis - 4days - no medical attendant
Informant: Bridget Donleavy - Killasona - present at death
Registered 11 December 1875 by C. F. Yorke, Registrar
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1875/020603/7229189.pdf
Birth Certificate, 24th January 1867, Killasona
Michael, son of Christopher Donleavy (farmer) & Mary Donleavy formerly McManus
Informant: Bridget Donleavy, Killasona, present at birth
Registered 2 February 1867 by Christopher F. Yorke, Registrar
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1885/10860/5965515.pdf
In the 1854 Griffith's Primary Valuation, I see:
Killasona Townland, Granard Parish, Granard Union, County Longford
Plot, Occupier, Immediate Lessor, Description, Area
15, Christopher Dunleavy, Christopher Nugent, House-Offices-Land, 18 Acres - 3 Roods - 0 Perches (in Statute Acres)
https://griffiths.askaboutireland.ie/gv4/z/zoomifyDynamicViewer.php?file=183109&path=./pix/183/&rs=2&showpage=1&mysession=2810692508208&width=&height=
18 December 1834 Census - Granard Parish, County Longford I found the following (unfortunately no ages or relationships are given):
Townland, Number, Name, Sex, Religion
Killasona, 3897, Patrick Dunleavy, male, RC
Killasona, 3898, Christopher Dunleavy, male, RC
Killasona, 3899, Margaret Dunleavy, female, RC
Killasona, 3900, Bridget Dunleavy, female, RC
https://registers.nli.ie/registers/vtls000632425#page/14/mode/1up
No Dunleavys were recorded at Killasona at the time of the 1833 Tithe Applotment Books of Granard Parish County Longford:
http://titheapplotmentbooks.nationalarchives.ie/reels/tab//004587446/004587446_00062.pdf
http://titheapplotmentbooks.nationalarchives.ie/reels/tab//004587446/004587446_00063.pdf
However, I see Pat Dunleavy recorded at the neighbouring Rossan Townland which is in Abbeylara Civil Parish (Granard RC Parish), County Longford as follows:
1833 - Pat Dunleavy, 9 Acres - 0 Roods - 0 Perches (in Irish Plantation Acres, 1 Irish Plantation Acre = c1.62 Statute Acres)
http://titheapplotmentbooks.nationalarchives.ie/reels/tab//004239502/004239502_00077.pdf
I believe this could well be Patrick Dunleavy, the father of Christopher Dunleavy who was recorded at Killasona Townland, Granard Parish, County Longford in 1854, especially as Killasona and Rossan are neighbouring Townlands and no Dunleavys were recorded at Rossan Townland, Abbeylara Parish, County Longford in 1854.
Baptised, 5 June 1806, Granard RC Parish, County Longford
Christopher, son of Patrick Ultagh & Bridget Molloy
Sponsors:Matthew McCormick? & Margaret? Masterson
https://registers.nli.ie/registers/vtls000632421#page/91/mode/1up
Married, 16 June 1793, Granard RC Parish, County Longford
Patrick Ultagh & Bridget Molloy
Witnesses: James Molloy & Michael Fanning
https://registers.nli.ie/registers/vtls000632421#page/116/mode/1up
Dunleavys/Ultaghs were recorded at Killasona Townland, Granard RC Parish, County Longford from at least:
28 April 1826, Mary Ultagh, Killasona
https://registers.nli.ie/registers/vtls000632422#page/169/mode/1up
Granard Graveyard, County Longford – Plot No.9, Section B
https://www.irishgraveyards.ie/plot.php?plotno=9&yardid=155§ion=B
According to this Irish Graveyards website she was aged 21
Mary, daughter of Patrick Ultagh and Bridget Molloy, above, would have been aged 24 as she was baptised on 25 October 1801, but she is still a possibility to be one and the same as this person.
Two further Ultaghs from Killasona appear in the Granard Parish Burial records:
5 April 1842, Bridget Ultagh, Killasona
https://registers.nli.ie/registers/vtls000632422#page/182/mode/1up
4 January 1844, Patrick Ultagh, Killasona
https://registers.nli.ie/registers/vtls000632422#page/184/mode/1up
The above Patrick Ultagh and Bridget Ultagh could well be Patrick and Bridget (Molloy) Ultagh.
2 Dunleavys/Ultaghs from neighbouring Rossan Townland appear in the burial records of Granard RC Parish, County Longford:
22 September 1792, Mary Ultagh, Rossan
https://registers.nli.ie/registers/vtls000632421#page/153/mode/1up
12 April 1806, Thomas Ultagh, Rossan
https://registers.nli.ie/registers/vtls000632421#page/159/mode/1up
The above Thomas and Mary Ultagh could possibly be Patrick Ultagh’s parents.
Rossan Townland in County Longford shares a border with Streete Parish and also with County Westmeath. There are Dunleavys buried in Boherquill Cemetery, Streete RC Parish, County Westmeath, but I do not have any details on them.
Another Christopher Dunleavy, who was married to a Mary Reilly, appears in Lough Gowna and Mullanalaghta RC Parish, County Longford baptismal records in the 1830's, at the same time as Christopher and Bridget (Molloy) Dunleavey were at Killasona in Granard RC Parish
And another Christopher Dunleavy was recorded at Clontumpher Townland, Killoe RC Parish, County Longford at the time of Griffith's Primary Valuation in 1854.
A Christopher Leavy was recorded at Cooleeny Townland, Longford RC Parish, County Longford at the time of the Tithe Applotment Books in 1823-1833.
Hoping the above is of interest,