John Dunn was born on March 13, 1847 and baptized on May 8, 1847 near Queanbeyan, the son of John Dunn, a shepherd at Woden (now part of the ACT) and Elizabeth Davis or Davidson. He met and married Catherine Elliot, the daughter of William and Ann, on May 26, 1873 in the Roman Catholic Church at Cooma. Catherine Elliott was born in the Cooma District.