Notes:

He likely emigrated to Canada with his parents, in about 1840.
All three of the original Callaghan brothers named their first-born sons Cornelius, strongly suggesting that this may have been their father's name.
In order to distinguish one from the other, they were assigned their father's name as their own middle name.
Cornelius seems to have always lived with his family, first with his parents, then with various siblings, working as a farm labourer.
He died at the age of 75 years, at home at concession 5, Lot 36 of Kidney disease.

Notes:

Denis was the oldest of the Callaghan brothers, and was the last to immigrate to Canada.
His younger brothers emigrated in 1826, and his son Murt emigrated in 1833.
But Denis remained in Ireland much longer, either to look after the home farm or perhaps to care for aging parents.
Denis, his wife and the remainder of his family likely came over in about 1840, at the same time that his son Thomas did.
Denis lived with his son Murt. on Con 5 Lot 36.
He was preceeded by his brothers Thomas and Daniel, and by his eldest son Cornelius.

Denis married Johannah CALLAGHAN about 1806. Johannah was born in 1789 in Cork, Ireland; died on 3 Nov 1866 in Marysville, Tyendinaga Twp, Hastings County, Ontario; was buried on 6 Nov 1866 in Marysville, Tyendinaga Twp, Hastings County, Ontario. [Group Sheet] [Family Chart]

Notes:

Johanna's maiden name was also "Callaghan," so it is presumed that if she were of a related family, she would have to have been at least separated by the three degrees of
consanguinity then prescribed by Catholic practices.

Cornelius married Ann TAVERNER in 1773. Ann (daughter of Thomas TAVERNER and Sarah GARDINER) was born about 1755; died in UNKNOWN. [Group Sheet] [Family Chart]

Thomas married Sarah GARDINER on 14 Feb 1756 in St Dunstan and All Saints, Stepney, Tower Hamlets, Middlesex,England. Sarah was born about 1725; died before 1825. [Group Sheet] [Family Chart]