Mary Lucretia Costello

Formerly of Greensburg, Mary Lucretia O’Neil Costello entered eternal life on February 16, 2025, at the age of 91 years. A beloved wife, mother, grandmother, sister, friend, and teacher, Lou died peacefully at Heart to Home in Minneapolis, Minnesota, surrounded by her family.

Born September 17, 1933, in Binghamton, New York, Lou was the daughter of James M. O'Neil and Mary H. Hogan O'Neil. Lou was a proud alumna of Seton Hill College, class of 1955, and was the first of the five O’Neil sisters to graduate from Seton Hill. Lou also earned a master’s degree in English Literature from Cornell University in 1960. She taught English in public schools in Binghamton, New York, and Montgomery County, Maryland. Lou also was an Admissions Counselor at Seton Hill.

Lou had a deep affection for the Sisters of Charity and the Seton Hill community, whose profound impact on her life filled her with gratitude and blessed her with lifelong friends. She served on the Seton Hill Alumnae Board, the Seton Hill Development Council, and multiple terms on the Seton Hill Board of Trustees where she was later named an Emeritus Trustee.

Lou delighted in her role as the eldest of the eight O’Neil siblings, and she remained close with them throughout her life. She most especially cherished and loved her role as Pat’s wife and mother to Pat, John, Libby, and Reeny. She prioritized family dinners – almost always three to four courses made-from-scratch – even if that meant eating famously late into the evening, as long as the family ate together. She deeply valued education and spent countless hours late into many nights at the kitchen table supporting her children in their schoolwork and academic pursuits.

Lou loved travelling to Notre Dame football games and hosting tailgates, vacations at Ocean City and Deep Creek Lake with her immediate family and the extended O’Neil family, and trips to Ireland with her husband and children. 

A woman of deep faith, Lou had a special devotion to the Blessed Virgin Mary and Saint Elizabeth Ann Seton. She was an active member of Blessed Sacrament Cathedral parish for almost fifty years until she moved to Minnesota six years ago.

Lou was predeceased by her parents as well as brothers Binghamton Police Chief James T. O'Neil, Edward M. O’Neil, and Kevin D. O’Neil; sisters Sharon O. Kahn and Eileen A. O'Neil; brothers-in-law Charles A. Reese and LTC Philip J. Kahn, Sr.; sister-in-law GunMarie O'Neil; nephews Ronald D. Davis and Christopher J. Reese; and her dearly beloved husband of more than 48 years, B. Patrick Costello, Esq.

Lou is survived by her four children: Col. B. Patrick Costello, Jr. (Mary) of Alexandria, VA; John M. Costello, M.D. (Doyle) of Mount Pleasant, SC; Elizabeth Costello Amaris (Troy) of Minneapolis, MN; and Maureen Anne Shinnick (Daniel) of Spokane, WA. Pat and Lou have eighteen grandchildren: Mary Kate, Patrick, Michael, James, and Colette of Alexandria; Jack, Liam, Colin, Michael, and Kevin of Mount Pleasant; Brendan, Maggie, and Anna of Minneapolis; and Paul, John, James, David, and Anne Regina of Spokane. Lou is also survived by her sisters Margaret C. Reese and Kathleen T. Isleib; sister-in-law Arlene Murphy O'Neil Longcoy and her husband Thomas H. Longcoy; sister-in-law Naomi Costello of Pleasant Unity, PA, and many treasured nieces, nephews, and cousins.

The family thanks the wonderful and loving caregivers at Heart to Home in Minnesota for the unending kindness and compassion they showed Lou as she progressed in her journey with Alzheimer’s Disease.

The family will receive friends at the Kepple-Graft Funeral Home, 524 North Main Street, Greensburg, on Friday, February 28, from 5 to 7 p.m. A Funeral Mass will be offered at Saint Joseph Chapel on the campus of Seton Hill University, Greensburg, on Saturday, March 1, at 11 a.m. Burial will follow at Saint Vincent Cemetery, Latrobe.

In lieu of flowers, the family requests that expressions of sympathy in memory of Lou may be made to Seton Hill University’s “Mary Hogan O’Neil and James Michael O’Neil Endowed Scholarship Fund,” One Seton Hill Drive, Greensburg, Pennsylvania 15601 https://alumni.setonhill.edu/GiveSHU, or to a charity of the donor’s choice.