Sister Mary Celestine Theriault, RSM

Please pray for the repose of the soul of Sister Mary Celestine Theriault, RSM (Margaret), who died on June 17, 2025, at the age of 97.

Originally from Presque Isle, Sister Mary Celestine was the youngest of six children born to Francis X. Theriault and Margaret Michaud. After graduating from Presque Isle High School and working a few years, she entered the Sisters of Mercy in Portland. There, she began preparing and learning about religious life while beginning studies at Saint Joseph’s College of Maine, earning a degree in education.

Sister Mary Celestine spent 20 years in elementary education, teaching in Portland, Brewer, Westbrook, Houlton, and Indian Island. She then began her second ministry as a religious education coordinator, serving at parishes in Presque Isle, Gardiner, and Westbrook.

Sister Mary Celestine was appointed coordinator of the Motherhouse of the Sisters of the Mercy from 1987-1994.  One of the joys of ministry in her later years was as liaison to the Mercy Associates. She nurtured the call of Mercy charism in places north of Portland. She received the blessing of many close friendships as they carried out the works of Mercy. She also served as a pastoral associate in Augusta and Bangor.