Robert (Bob) Rengstorf, age 84, of Stone Lake, Wisconsin, passed away peacefully at his home on Friday, November 28, 2025.

Bob was born on December 2, 1940 in New Ulm, Minnesota to Frederick and Ruth (Walz) Rengstorf. He grew up in Winthop, MN with his brother Richard and graduated from Wintrop High School. He later attended St. Cloud and Mankato State Universities earning a Bachelor of Science in Biology. Bob also earned many post graduate credits to stay current in his field.

Bob had an adventurous, generous, kind and strong personality. He had many interests including fishing, hunting, woodworking, traveling, music, gardening, birding, geocaching, his golden retrievers and volunteering with the Stone Lake Lions. Bob taught biology for 35 years at Hudson WI High School.

Bob married Linda Pfister on May 25, 1963. They lived in Afton, MN for many years. They had two children, Lance and Sara. He later married Judith Favell on August 15, 1994. Bob and Judy traveled extensively and after retiring moved up to the Hayward area.

Bob is survived by his wife Judith Rengstorf, his son Lance (Jessica) Rengstorf, and their daughters Brielle and Emmelina; his daughter Sara Rengstorf and her daughter Madeline. He is also survived by many cousins and good friends. He was preceded in death by his parents and his brother Richard Rengstorf.

In keeping with his wishes, no funeral or visitation will be held. A private gathering will be held later by the family. If desired, the family suggests that remembrances be made to the Courte Oreilles Lake Association or to the Northwoods Humane Society.

Last Update: Dec 04, 2025 9:06 am CST