The family and friends of Lilly K. Jansen, a 21-year-old resident of Dieterich, Illinois, are remembering their beloved daughter after she passed on Wednesday, January 28, 2026, at Barnes Jewish Hospital in St. Louis. Born on August 18, 2004, in Mattoon, the daughter of Matthew and Leslie (Willenborg) Jansen, Lilly was a bright, determined young woman whose life was filled with promise, kindness, and deep love for her family.
Her sudden death has left her parents, siblings, grandparents, fiancé, and the Dieterich and broader Southern Illinois community in profound grief, as they reflect on a young life cut far too short but lived with joy, purpose, and compassion.
Lilly was attending Southern Illinois University Edwardsville, where she was pursuing a degree in civil engineering with focus and enthusiasm. She had already accepted a position with CDI in Effingham and was eagerly preparing to begin her career following her planned graduation in May 2026.
Her academic journey reflected a young woman who excelled in challenging coursework, collaborated well with peers, and approached her studies with the same determination she brought to every part of her life. Those who knew her at SIUE recall a student who was thoughtful, supportive, and genuinely excited about the future she was building.
At the center of Lilly’s world was her family, whom she loved deeply and unconditionally. She is survived by her parents Matthew and Leslie of Dieterich; her brother Cole of Dieterich; her sister Katelyn (fiancé Jake Herd) of Dieterich; her future fiancé Will Overton of Altamont; and her grandparents Raymond and Linda Willenborg of Teutopolis and Marilyn Jansen of Neoga.
Lilly cherished time spent with her loved ones—whether family gatherings, quiet evenings at home, or shared adventures—and always made sure those closest to her felt supported, appreciated, and loved. Her future fiancé Will was her partner in dreams and daily life, and together they looked forward to a shared future that was tragically interrupted.
Lilly was known for her bright spirit, her kindness, and the way she brought warmth and positivity to those around her. In Dieterich and the surrounding communities, she was remembered as a young woman with a gentle heart, a quick smile, and a genuine desire to make others feel valued.
She formed strong friendships and maintained close ties with family, always ready to offer encouragement, share laughter, or simply be present when needed. Lilly lived with optimism, resilience, and an open heart, leaving behind memories of joy and love that will continue to comfort those grieving her absence.
A Mass of Christian Burial were held at 10:30 am on Tuesday, February 3, 2026 at St. Aloysius Catholic Church, Bishop Creek, with burial in the church cemetery. Visitation were held from 4:00 pm to 7:00 pm Monday at the church.
