Mary Helen Marquess

Mary Helen Marquess (nee Imus), of O Fallon, MO, passed away, after a courageous battle with dementia, on Friday, February 6, 2026, at the age of 78. Beloved wife of Robert E. Marquess; cherished daughter of the late Robert and Gertie Imus; devoted mother of Rob (Lisa) Marquess; loving grandmother of Joshua (Lauren) Marquess, Cole Marquess, and Abbey Marquess; dear sister of Clarence (the late Kim) Imus, Martha (Rick) Francis, Shirley (Byron) Marcum, Louise (David) Smith, Vivian Perkins, Faye (Larry) and the late Barb Sharkey; precious aunt of several nieces and nephews.

She married Robert E. Marquess on September 3, 1966. She was employed as a bookkeeper and building manager at Three Flags Center Town House in St. Charles, MO and The Mary K in Hazelwood, MO until her retirement. She loved her family and friends with a passion. Mary was deeply loved and will be greatly missed by all who knew her.

In lieu of flowers, memorials may be made in Mary's name to the Alzheimer's Association.