Mary T. O'Sullivan (Terry, Mama O.), 81, a long time resident of Clinton Corners, NY, and a former resident of New York City, passed away Sunday, November 16, 2025.  Born October 28, 1944 in New York City, she was the daughter of the late Martin J. McDonnell and Catherine (McGrath) McDonnell.

Terry was a teacher's aide at BOCES for 20 years.  She enjoyed spending time with her family especially her grandchildren including trips to Maine and The Adirondacks.  She was also a member of the local chapter of The Red Hats (The Dazzling Dames).

On September 30th, 1967, she married John D. O'Sullivan (Jack) at Our Lady Queen of Martyrs Church in New York, NY.  She is survived by her husband and two children, son, John P. O'Sullivan and wife, Catherine O'Sullivan and daughter Mary E. O'Sullivan and 12 grandchildren, as well as numerous nieces and nephews.  She is predeceased by her sister, Veronica E. Barron and her brothers, Martin J. McDonnell Jr. and James T. McDonnell.  Calling hours are 3 to 6 p.m. Thursday, November 20 at Allen Funeral Home 1605 Main Street, Pleasant Valley, NY. A funeral service will be held at 5:30 pm during the calling hours at the funeral home.

In lieu of flowers, a donation in memory of Mary T. O'Sullivan can be made to Tunnel to Towers Foundation.