I wonder whether your Jack McGovern could be related to a great-great-great grandfather of mine, a Robert McGovern, farmer in Co. Cavan. His daughter Eliza McGovern, born about 1803 in Co. Cavan, married one Thomas Condron in about 1822 in that county. (Thomas was born about 1803 in the Parish of Crosserlough, Co. Cavan - his father was a farmer of the same name.)
I do not know the names of the wives of Thomas Condron senior or Robert McGovern, except that McGovern's wife's Christian name was Catherine.
Thomas Condron junior, his wife Eliza and family (ten children) emigrated to Australia about 1852. I don't know if any of my McGoverns (bearing that name) came here.