Luke O'Connor, the first soldier who won the British military award, the Victoria Cross for his actions at the Battle of Alma during the Crimean War was born in Hillstreet, County Roscommon, very near to Elphin.
Its Cathedral, which was originally established in the County Roscommon town of Elphin, is now in Sligo.
These were John Law (1745–1810), bishop of Elphin; Thomas Law (1759–1834), who settled in the United States in 1793, and married, as his second wife, Eliza Custis, a granddaughter of Martha Washington; and George Henry Law (1761–1845), bishop of Chester and of Bath and Wells.
Laurence Gillooly, an Irish Roman Catholic clergyman who served as the Bishop of Elphin
He was born either in the townland of Pallas, near Ballymahon, County Longford, Ireland, where his father was the Anglican curate of the parish of Forgney, or at the residence of his maternal grandparents, at the Smith Hill House in the diocese of Elphin, County Roscommon where his grandfather Oliver Jones was a clergyman and master of the Elphin diocesan school, and where Oliver studied.
Since the 19th century, St Tassac has sometimes been confused, with Saint Assicus of Elphin, County Roscommon, who had the same types of skill and is said to have died in the same year, and with St Assam (or Assan).
He held a synod at Galway in 1523, attended by bishops of Kilmacduagh, Achonry Clonmacnoise, Kilfenora, Ross, in addition to representatives of the dioceses of Elphin, Killala and Armagh.