Mary T. (Sheehan) O'Brien, age 87, of Lincoln, died on May 21, 2020. She was the beloved wife of the late Daniel F. O'Brien who died in 2003. Born on September 21, 1932, she was the daughter of the late John and Mary (Riley) Sheehan. Mary was born and raised in Cambridge, MA before marrying Dan and moving the family to Burlington and then settling in Lincoln. Mary worked for many years for the Town of Lincoln at the Lincoln Public School. She began as a Nurses Aid and was well known for her "Magic Crackers" when the students had an upset stomach. She later became the principal's assistant. Upon retiring from the Lincoln Schools, she assisted Bemis Hall in scheduling events. Mary will be remembered as a fun loving, life of the party woman. She was the first on the dance floor at every wedding and one of the last to leave the party. She loved to sing and dance and have fun with all her friends and family members. She was "Queen of the chicken dance" and loved her Irish heritage. Mary was honored with the naming of the road she lived on. Marys Way was named after her and many other Mary's from the original neighborhood. Her legacy will live on in Lincoln forever on Marys Way. It was a very proud moment in her life. She is survived by daughter Cheryl O'Brien of Hudson MA, son Daniel O'Brien, III of Lunenburg MA, daughter Meg (Mary) and her husband Ralph of Marlborough MA, daughter Cathy O'Brien & her partner Jim Durkin of Lincoln MA (whom she lived with for the past year), her two cherished granddaughters, Colleen Anderson of Denver CO and Elizabeth Anderson of Marlborough MA. Mary leaves behind many loving and adored nieces, nephews, and many friends, in addition to several sisters in law and one brother in law. She was predeceased by two brothers, Jack (John) Sheehan formerly of Somerville, and Edward Sheehan formerly of Arlington. She was well cared for during the length of her illness by a dedicated, passionate and caring group of nurses aids - a large thank you from the O'Brien family to this group of ladies that assisted us every day. Due to current restrictions in light of COVID-19, immediate family members will gather privately in the Dee Funeral Home, followed by a private burial service at Lincoln Cemetery. In lieu of flowers, contributions in her memory may be made to MSPCA-Angell, Attn: Donations, 350 South Huntington Ave, Boston, MA 02130 or online at www.mspca.org (She always referred to Cathy's house as the Funny Farm). Arrangements are under the care of Dee Funeral Home & Cremation Service of Concord.