Okay... here's a roundabout way that might help you find out where Sarah was from in Ireland, if I have all my facts straight

Bear with me...
Given the family in 1861 above, we can try to follow Sarah's brother John through the censuses. Since he was born in Ireland, there is always hope that some record, will say exactly where.
In 1871 he was still with his family and is a painter:
1871
86 High St, Airdrie, New Monkland, Lanarkshire
Patrick Barns, 65, Head, born Ireland, Labourer
Ann Barns, 61, Wife, born Ireland
John Barns, 21, Son, born Ireland, Painter
William Kelly, 11, Grandson, born Coatbridge, Lanarkshire, Scholar
Extra bonus is William Kelly
By 1881 he is married with a child:
1881
35 Doncaster St, Kelvin, Glasgow Barony, Lanarkshire
John Burns, 28, Head, born Ireland, House Painter
Margt Burns, 25, Wife, born Edinb, Midlothian
Jane Burns, 7, Daughter, born Glasgow, Lanarkshire, Scholar
Now here is where we get our break (perhaps

)
In 1891 he is in prison

(interesting the things that make us happy

)
1891
H M General Prison, Edinburgh Road, Perth
John Burns, 41, Prisoner, born Ireland, Painter
Wife and daughter are on their own:
1891
207 Gairbraid St, Maryhill, Barony, Lanarkshire
Margaret Bruns, 35, born Edinbro, Midlothian, Power Loom Weaver
Jeanie Bruns, 17, Daur, born Glasgow, Lanarkshire, Power Loom Weaver
By 1901 he is out, but the family is still separated:
1901
61 Edington St, Milton, Glasgow St George in the Fields, Lanarkshire
John Burns, 52, Head, born Ireland, House Painter
1901
435 Dobbies Loan, St Rollox, Glasgow Port Dundas
William McLellan, 27, Head, born Glasgow, Lanarkshire, Stamper General Po
Jeanie McLellan, 27, Wife, born Glasgow, Lanarkshire
Margaret Burns, 45, Mother In Law, born Edinburgh, Midlothian, Power Loom Weaver
So... two thoughts:
1) Did his wife get public assistance while he was in prison? If so, there may be a record.
2) The records for Perth Prison exist at NAS
http://www.nas.gov.uk/guides/crime.asp
Perth (General) Prison 1846-1913
HH21/47/1-8, HH21/48/1-5
Here's hoping that the prison records will state his place of birth! [-o<
All the best,
Sarah