1949: On 1 October 14 nuns from Ireland arrive, to make the first foundation of Cistercian nuns in the United States. 21 November, ceremony to establish monastic enclosure, by the archbishop of Boston, Richard J. Cushing. 8 December: first perpetual profession: M. M. Michael Howe.
1950, 15 May: death of the mistress of novices, M. M. St. John. 10 November: change of stability from Glencairn to Mt. St. Mary’s, Wrentham. 13 November: election of R.M. Mary Bernard O’Donnell as the first abbess of Mount Saint Mary’s.
1955 the founders return to Glencairn.
1960 general chapter: a foundation is authorized for Argentina; it was never realized.
Abbey Retreat house : 3 rooms (4 persons) ; small apartment; McMahon Retreat House: 9 rooms (12 persons), dining room, meeting room