Published on December 30, 2025 9:55 am
Last Updated on December 30, 2025 9:55 am
John Mark Duncan, 66, of St. Elmo, Illinois passed away on Christmas Eve, 2025. The world lost a big hearted, Christ centered, teddy bear of a man.
Mark was born January 10, 1959, in Pampa, TX to Bill and Katherine Duncan. He graduated from Amarillo High School, Amarillo, Texas in 1977, then went on to graduate from West Texas A&M University, Canyon, Texas in 1982 with a bachelor’s degree in Plant Science. Mark’s love of nature and passion for science led him to his first job in Guthrie, Oklahoma to work for Art Maton in the greenhouse business where he met Diane Mary Maton, the love of his life, and Art’s daughter. They were married on March 5, 1983. The birth of their daughter Megan in 1986 brought Mark great joy. Throughout his professional life, Mark worked as an oxygen specialist, contributing his skills to companies such as Lincare. His career in healthcare demonstrated his dedication to helping others and his commitment to his profession. Mark’s greatest love was his relationship with Jesus Christ. He enjoyed working with teenagers, singing in the choir, and serving others in the homeless community. He was an elder for many years and started a prayer ministry at Connection Church. Mark adored his family and spent countless hours investing in their lives and activities. If Mark wasn’t with his family, friends, or church, you could often find him fishing in the lakes surrounding St. Elmo. His hobbies included painting model figurines, listening to music, and enjoying lunch dates with family and friends. He also cherished spending time with his beloved dog, Scooby. An avid sports enthusiast, Mark followed college sports, especially the Fighting Illini, and the NFL.
He was preceded in death by his parents, and his in-laws, Art and Joyce Maton of Pana.
He is survived by his wife of 42 years, Diane Duncan of St. Elmo, his daughter Megan and husband James McDonald of Ramsey, and three grandchildren, Bladyn, Adilynne, and Merrick. He is also
survived by his stepmother, Jenny Duncan of Lubbock, Texas, his sister Sarah and husband Greg Houlette of Amarillo, Texas, his sister, Ann and husband Alan Levy of Laguna Beach, California, stepbrother, David Hurt and wife Susan of Ransom Canyon, Texas, stepbrother, Jeff Hurt and wife Sondra of Carrollton, Texas, brother-in-law, Arthur Maton of Fayetteville, Arkansas, brother-in-law, Tom Maton and wife Sheila of Pana, and many nieces, nephews, cousins, and friends.
Though Mark was known for his gentle kindness and loyal presence, his sense of humor and quick wit will be missed the most.
A memorial service will be held at 3:00 PM, Friday, January 2, 2026 at Connection Church in St. Elmo with Pastor Tim Caraway officiating. Visitation will be held prior to the service from 1:30-2:45 PM Friday at the church. Memorials may be made to Connection Church or to the Breast Cancer Research Foundation. Online Condolences & Obituaries available at www.hohltandfilefh.com Arrangements by Hohlt & File Funeral Home, Vandalia, IL