Mary Ann Frances Knoll Pfeiffer, age 99, died on June 5th, 2023 at Chaska Heights Senior Living, Chaska, MN. She was born to George and Elizabeth (Dankbar) Knoll Nov. 5th, 1923 in Garner, Iowa. Mary Ann graduated from Garner High School and Otumwa Heights College, Otumwa, Iowa and also attended Drake University in Des Monines, and Mankato State University in Mankato. She married Charles Kenneth Pfeiffer on Nov. 5th, 1947 in Marshalltown, Iowa. She was office manager for Pfeiffer Heating and Air Conditioning until the death of her husband in 1988. Mary Ann worked at St. John the Baptist Catholic Church as assistant secretary and REM Heartland both in Mankato for 12 years. As a woman of faith, she was active in St. John the Baptist Catholic Church for 44 years and was a member of River of Life Prayer Community. She volunteered for Vine Faith in Action and Habitat for Humanity in Mankato. Mary Ann moved to Eden Prairie in 2010 and to Chaska in 2018 where she made many friends. She was active in bible study and her resident association. Her interests included her devoted family, reading and traveling. Mary Ann was preceded in death by her husband Charles Kenneth Pfeiffer, parents George and Elizabeth (Dankbar) Knoll and brothers Edmund and Anthony. She is survived by her son Greg (Susan Bohm) and their children Anne (Andrew Bernhardt), Mark (Debra Wilensky) and Brian, her son Tom (Joyce Gunsallus) and their children Laura (Ryan Dykstra), Beth and Joe, her son Dan (Shelly Schulz) and their children Andy and Lucas, her son John (Carrie Zimmerman) and her daughter Mary (Doug Pernula) and their children Katie (Cameron Hagen) and Ted. She has four great-grandchildren Julianna Dykstra, Madeleine Pfeiffer, Hannah Bernhardt, and Halle Hagen. A mass of Christian burial will be held at St. John the Baptist Catholic Church in Mankato on June 12th, 2023 at 11:00am. Visitation will be at 10:0am. Burial will be at Calvary Cemetery following mass. Lunch will be served at the church after the burial. In lieu of flowers, memorials in Mary Ann’s name may be directed to St. John the Baptist Catholic Church, Vine Faith in Action, or Habitat for Humanity all in Mankato.