Doris Clausius Mosser of Fontana and formerly of Rockford, Illinois, passed away on Feb. 16, 2026, due to complications from a fall. Doris was born on April 30, 1939, to Dr. Gerhard Clausius and Ella (nee Carlson) Clausius in Belvidere, Illinois. Doris, her twin brother Donald and older brother Gerry grew up in Belvidere. They began spending their summers in Fontana in 1943, when their parents bought a cottage in Buena Vista, on Lake Geneva.
Doris graduated from Belvidere High School in 1957, and from there went to Lake Forest College in Lake Forest, Illinois. A member of Chi Omega sorority, she graduated in 1961 with a degree in English and began a career in education in Rockford.
Doris met her husband Don, a friend of both her brothers, on the front porch of her parents’ cottage. They began dating in the fall of 1961, married on July 28, 1962, and started building a life of family, friends and adventures together.
Doris volunteered and held leadership roles in Rockford while their three children were young. She was active in several organizations, including Our Saviors Lutheran Church, the Junior League of Rockford (where she served a term as President), the Rockford Symphony Orchestra, the Discovery Center and Century Club. In 1983 she became the Director of SOURCE (Service of Uncovering Resources in the Community for Education) for the Rockford Public Schools. In 1997 she received the Administrator of the Year award in the Those Who Excel awards. From 1980 through 1985 Doris was a member of the Rock Valley College Board of Trustees, and served a term as Chairman of the Board.
Doris and Don retired to Fontana and became active in their community, including the Community Church of Fontana, Open Arms Free Clinic and AAUW. After Don passed away in April of 2019, Doris remained actively engaged with their community.
Doris and Don cherished their family, friends and communities. They are survived by their children, David (Leah) Robberts-Mosser of Urbana, Illinois, Michael Mosser of Chicago, and Susan (Gat) Caperton of Berkeley Springs, West Virginia; their granddaughters Eliza, Katie and Evie Caperton, and Chloe and Violet Robberts-Mosser; sister-in-law Gwen Clausius; brother-in-law Larry Pierce; many beloved nieces, nephews, great-nieces, great-nephews and one adorable great-great-nephew.
The family will be receiving friends at Toynton Walworth Funeral Home, 328 Kenosha Street in Walworth on Friday, Feb. 27, from 5 until 8 p.m. A Memorial Service will be celebrated on Saturday, Feb. 28, at 2 p.m. at the Community Church of Fontana, 275 Kinzie Avenue in Fontana.
In lieu of flowers, memorials may be made to the Discovery Center, 711 N. Main Street, Rockford, IL 61103; Open Arms Free Clinic, 205 Commerce Street, Elkhorn, WI 53121; the Community Church of Fontana, 275 Kinzie Avenue, Fontana, WI 53125; or to an organization of the donor’s choice.
Arrangements made by Toynton Funeral Home in Walworth. For more information, call (262) 275-2171.