Mary Katherine Deem, 74 of Belpre, Ohio died on February 14, 2020 at her residence. She was born in Cleveland, Ohio on July 30, 1945 and was the daughter of the late Tom and Katherine Mulligan. She was a 40 year member of the St. Ambrose Catholic Church parish, was an associate of the School Sisters of Notre Dame. She passed on her lifelong love of horses as a 4-H advisor for 35 years. She volunteered for RSVP, BAM, and the Belpre Historical Society Museum. She worked at Arthur N. Gustke Children's Home Society for 15 years and as a Doctor's Assistant for Dr. P.J. Landsman for 15 years. She is survived by her husband of 55 years, Roger Deem, son Ed (Cathy) Deem, daughter, Sandy (John) Vincent, Grandsons, Nathan (Liza) Vincent and Andrew (Kelsey) Vincent, great grandson, Aden Vincent and cousins who were as close as brothers, James Thomas and Frank (Leslie) Thomas. She was preceded in death by her parents. Mass of Christian Burial will be conducted on Tuesday at 10:00 AM at the St. Ambrose Catholic Church with Father Bob Gallagher as Celebrant. Friends may call at the Leavitt Funeral Home, Belpre on Monday from 2:00 to 4:00 PM and 6:00 to 8:00 PM. In lieu of flowers, donations can be made to the Humane Society of the Ohio Valley, 90 Mount Tom Rd., Marietta, Ohio 45750. Online condolence may be made to the family at www.LeavittFuneralHome.com