He was the son of William Sandes and Margaret Creagh. He was born at Sallow Glen, near Tarbert, County Kerry, where the Sandes family had been settled for several generations. He married Mary Anne Dickson, daughter of Samuel Dickson of County Limerick, and they had four children.
Among his students at Trinity College was the eminent barrister and author Gerald Fitzgibbon, who remembered with gratitude that it was Sandes who advised him, despite his lack of money or influential connections (Fitzgibbon was a small farmer's son), to persist in a career in the law.
A much younger cousin, who was also named Stephen Creagh Sandes, was the father of Elise Sandes, founder of a welfare movement for soldiers which survives today.
Elise Sands, cousin of the bishop and founder of a leading welfare movement for soldiers
^Handbook of British Chronology By Fryde, E. B;. Greenway, D.E;Porter, S; Roy, I: Cambridge, CUP, 1996 ISBN0-521-56350-X, 9780521563505
^DEATH OF THE BISHOP OF CASHEL, WATERFORD, &c The Standard (London, England), Friday, November 18, 1842; Issue 5729. 19th Century British Library Newspapers: Part II
