Margaret A. O'Sullivan, 54, of Amherst, NY, passed away on June 2, 2022 at Erie County Medical Center.  Born in Buffalo, NY, she was the daughter of Janet (Carlin) O'Sullivan and the late Patrick O'Sullivan.

Margaret was a graduate of Mt. Mercy Academy and earned her Associate's Degree from Trocaire College.  She was employed as an IT Analyst with Merchants Insurance Group in Buffalo, NY.   She was a member of the I.U.A.A. Parade Committee, the Buffalo Irish Center, and was a Spokesperson for Upstate New York Transplant Services.  She enjoyed interior designing, shopping, attending concerts, donuts, and spending Summer Thursdays at the Irish Center.  Above all, she cherished the time she spent with her children and grandchildren.

In addition to her mother, Margaret is survived by her daughter, Heather (Jason) Pascall-Nagy; her grandchildren, Quinn, Connor, Caleb and Hunter, and her granddogs, Trixie and Bailey; her loving devoted companion, Peter M. Heffernan and his children, Leanne (Rick) Pilarski and Kevin (Krista) Heffernan; her siblings, Michael (Jane) O'Sullivan, Rick O'Sullivan, James (Sharon) O'Sullivan, John O'Sullivan, Stephen O'Sullivan, Noreen (late Paul) Hoeflich, and Rachel (Matt) Steinbroner, as well as many nieces, nephews, aunts, uncles cousins, and dear friends.

Visitation will be held on Tuesday, June 7 from 4 – 8 PM at Castiglia Funeral Home, Inc., 873 Abbott Road, Buffalo, NY 14220.  Margaret's Mass of Christian Burial will be held Wednesday at 11 AM at St. Teresa Church, 1974 Seneca Street, Buffalo, NY 14210.  Everyone please assemble at church.  Interment in Holy Cross Cemetery, Lackawanna, NY.  If desired, memorial offerings may be made to the Juvenile Diabetes Research Foundation, https://www.jdrf.org/ .  Visit mjcoluccifuneralchapel.com for online condolences.