Mark Hapgood Stiefel

Mark Hapgood Stiefel of Winchester, California, passed away on September 28, 2026, at the age of 79. He was a dairyman, a sailor, and above all, the heart of a big and loving family.

Mark was born on June 11, 1947, and grew up in Artesia, California, when it was still dairy country. He studied Dairy Science at Cal Poly San Luis Obispo, graduating in 1969. After college, he came home to the work that would be his life’s calling. As Southern California's dairies moved east, Mark moved with them, first from Artesia to Chino. In 1989 he built a new dairy from the ground up in Winchester. Stiefel Dairy on Holland Road was his life's work. Cows don't take days off, and neither did Mark. He worked seven days a week, year after year, taking great pride in his work and in doing things the right way.

Mark worked hard, but he also knew how to enjoy life. He loved the ocean, and some of his happiest days were spent at the beach or under sail. He sailed to Catalina and raced down the coast to Ensenada with his brother, Mike. Those adventures and memories were a special part of who he was. He was also a self-trained chef and really enjoyed experimenting in the kitchen. Beware of the infamous Troubadour beans!

Above all, Mark loved his family. He was a devoted father and a fun, deeply loving grandfather. He had a gift for bringing people together, and made it a priority to keep family members connected to one another. That may be his greatest legacy: a family that knows and loves each other because he saw to it.

Mark is survived by his children, Julie Kusiak, Marcia Stiefel, Jack Stiefel and Matt Stiefel and his brother Mike Stiefel. He is also survived by his beloved grandchildren, Tyler Mason, Ricquel Crouse, Ava Miller, Troy Stiefel, Elise Stiefel, Sofie Stiefel and Simone Stiefel, a large and loving extended family, and many wonderful lifelong friends. Fair winds and following seas, Mark. You are deeply loved, and you will be deeply missed. The memories you gave us, the hard work, the laughter, the off-road adventures, and most of all the love you had for your family will live on forever in all of us.

A Celebration of Life will be announced later this year.