Mark Douglas Plegge

Mark Douglas Plegge, aged 60 of O’Fallon, IL, passed away peacefully at his sister’s residence in Vienna surrounded by his family.

Mark was born June 9, 1965, in Jefferson City, a son to the late Dr. Eugene Plegge and Evelyn (Pohlmann) Plegge who survives of Linn.

Mark was a 1983 graduate of Linn High School and a 1988 graduate of the University of Missouri where he received degrees in both Electrical Engineering and Computer Engineering. He was employed as a Civil Servant with the United States Air Force at Scott Air Force Base in Belleville, IL.

Mark selflessly dedicated 35 years to civil service and was both a leader and mentor to hundreds of colleagues. He was a Cyber Planner and Mission Element Lead on a 39-member cybersecurity team, managing and executing defensive cyberspace operations supporting all military branches. He was responsible for operational mission planning, coordinating and deconflicting mission requirements, and the presentation of Combat Mission Ready forces to defend the nations' nuclear assets, space and logistics architecture, and foreign policy interests.

Mark was a member of St. John’s United Methodist Church in Linn and of the Linn Masonic Lodge. Mark enjoyed watching the St. Louis Blues, St. Louis Cardinals, and Mizzou Tigers, and participating in sports like hockey and softball, fishing, and deer hunting. He enjoyed reading, listening to a variety of music, collecting knives, traveling, and spending time with his family and friends.

In addition to his mother, Evelyn, Mark is survived by one sister, Debra Henderson and her husband Carl of Vienna, three nieces, Sarah (Matthew) Stratman of Argyle, Amanda (Justin) Fagre of Meta, and Katherine (Nicholas) Smith of Harrisonville, one nephew, Austin (Anastasia) Henderson of Vienna and five great nephews, Jack Stratman, Jase Smith, Clemens Fagre, and Enrique and Vladimir Patino.

Visitation will be held from 4:00 p.m. until 7:00 p.m. on Sunday, July 20, 2025, at Morton Chapel in Linn. Masonic Services will begin at 3:30 p.m.

An additional visitation will be held from 9:00 a.m. until time of service at 10:00 a.m. on Monday, July 21, 2025, at St John’s United Methodist Church in Linn. Funeral Services will begin at 10:00 a.m. with Rev. Kayla Beard officiating. Interment will follow in the St Paul’s Cemetery in Bay.

Expressions of sympathy may be made to St Paul’s Cemetery or to St Jude’s Children’s Research Hospital.