Sr. Mary Estelle Cunningham was born Margaret Cunningham in 1898 in Kilbaha, Newtownsandes (now Moyvane), Co. Kerry to Richard Cunningham and Brigid Dore.

At the age of 17 she and her older sister Johanna travelled to Concordia, Kansas - where a distant relative, John Francis Cunningham, was a bishop - to enter the convent of the Sisters of St. Joseph.

Sr. Mary Estelle later moved to Belvidere, Illinois where she worked as a nurse for over 30 years at St. Joseph's Hospital. In 1973, due to frail health, she returned to Concordia where she continued to help with nursing duties. She died in Concordia in 1987 aged 89.

Johanna, Sr. Mary Estelle's sister, became Sr. Mary Ellen and worked as a nurse in El Paso, Texas for a time before returning to Concordia to work in St. Anthony's Hospital. Sr. Mary Ellen died in Concordia in 1989 aged 93.