John McKenna born c1817 in Gibralter Monoghan.,Ireland. He went to Austraia before 1846 because he married Elizabeth in Australia then. Not sure if he was a convict or came free. Searching for info on his parents
Gibraltar is also I think known as Garran Otra. Civil Parish Tehallan, PLU Monaghan.
The townland of Garran Otra or Gibraltar (H725 345) is 6 kilometers east of the town of Monaghan, is immediately west of the townland of Alkill, immediately east of the townland of Carrowkeel, and lies between Alkill and Carrowkeel..
I think the catholic parish is Tyholland for which baptisms are only available from 1835 so John's baptism would be there (if he was catholic?) but maybe related McKenna's would be?