It ceased operations in 1978 due to the increasing trend away from single sex higher education which in turn led to a decline in enrollment from a high of about 500 students to just under 200 at the time of the closing.

For many years, "The Mount" functioned as the sister school of the formerly all-male Saint Anselm College in Goffstown, New Hampshire, and the two institutions carried on a particularly close academic and social affiliation.

Throughout the existence of the school, this building housed nearly all academic and administrative facilities as well as several auditoriums, a ballroom, a chapel, a dining hall, a gymnasium, and dormitory rooms for resident students.

For its part, Notre Dame College, the other four-year school that closed, was not saved by coeducation because its campus was completely hemmed in by private homes in a residential neighborhood, thereby precluding any opportunities to expand its buildings and resources.

However, unlike Rivier College, which not only adopted coeducation but also created baccalaureate as well as master's degree programs in such fields as administration and management, communications, computer science and technology, fine arts, and additional health science fields which could be pursued during the days, evenings and weekends, Mount Saint Mary remained a traditional undergraduate day college for women with degree programs focused only on the liberal arts, nursing and teacher education.

Consequently, the school would steadfastly resist abandoning its genteel image and traditions for the sake of survival, and in May 1978, after 44 years of educating young women, Mount Saint Mary graduated its final class of students.