MAHON - Margaret (Gretta) of Wantagh passed away peacefully in her sleep on December 28, 2024. Formerly Sr. Mary Harold CSJ of Brentwood, she was born on February 10th, 1931 to her loving parents Bridget and William Mahon. Devoted sister of Brigid Boyle and cherished sister-in-law of Monica Mahon, she is predeceased by her brothers Anthony Mahon and William Mahon and sister-in-law Betty Mahon. She is survived by many beloved nieces, nephews, grand-nieces and grand-nephews, cousins and dear friends. Family will receive friends on Thursday, 3 pm - 7 pm, at the Charles J. O’Shea Funeral Homes, 603 Wantagh Ave (Exit 28N SS PKWY) Wantagh, NY. Mass of Christian Burial will be held on Friday, 11:15 am, at St. Frances de Chantal Church. Interment to follow at Holy Rood Cemetery, Westbury, NY. osheafuneral.com