Cosgrove McCusker Surname

Hi there

I am hoping someone can help me get through a roadblock in my family tree.  I am trying to trace back through my Cosgrove family tree.

My great Grandfather Charles Joseph Cosgrove was born 1857 in Aughawillan in the Parish of Carrigallen he joined the RIC in 1876 and was transferred to Belfast as the RIC had a rule that you couldn't be a policeman in the same parish as your family from what I understand.

He had a brother John Cosgrove born 1847 who died when he was 21 so around 1868 but I dont know anything else about him, Bernard Cosgrove born 1851, Margaret born 1855 who married Patrick Kennedy and later moved to America, Anne Cosgrove who married Daniel Gormley and also later moved to America and Michael born in 1849 who stayed and married Mary Gormley and was a farmer like his father Patrick.  Michael and some of his boys Bernard b. 1886, Charles b. 1888, John b. 1890, James b abt. 1892 and Patrick b. 1894 may have also used the surname McCusker.

In the 1901 census Patrick was the head of the family and 84 and his son Michael and wife Mary and their children Bernard, Charles, John, James and Patrick all lived at the house.

Patrick Cosgrove was born 20 May 1816 and married Anne Crossan who was born about 1818 & died about 1893, Patrick died 9 December, 1906 and was a farmer his whole life.

His father was John Cosgrove born about 1790 and died about 1860 and married Mary Lorty if I have deciphered the handwriting correctly.

Any information on Patrick b 1816 or John b abt. 1790 both of whom may have also used the surname McCusker are the ones I am stuck on as there are very few records online for these dates.

If anyone can help I would love to hear from you.

Thanks so much

Sharon Cosgrove