Probably Ireland.

Charles is listed as Cath in 1851

1841, Rushen, district 5 page 15, Ballacorkish
James Mc Card, 35, agricultural labourer, Ireland
Susan, 35, Ireland
Susan, 7, Ireland
James, 4, Isle of Man
Thomas, 1, Isle of Man

With William & Ellinor Cubbon, Colby
Ellin Macard, 5, Isle of Man

Rushen, district 5, page 16, Scealaby
Arthur Mc Ard, 30, male servant, Ireland
Edward, 12, male servant, Isle of Man