Mary Ruth Grellinger

Mary Ruth Grellinger was born in Milwaukee, Wisconsin, on September 8, 1948 to Alvin and Ruth Grellinger.

Mary met Chris Koch, also from the Milwaukee area, and they were married on June 7, 1970. They moved to and made a home in Jackson, Wyoming, in 1972, where they welcomed their son Rhett in January 1976 and their daughter Hanna in May 1977. As a family, they spent most of their time outdoors up the Gros Ventre, in the Grand Tetons, and riding motorbikes and horses. She always said she was a city girl, but she rolled with it and rolled with it well.

While living in Jackson, Mary worked for St. John’s Hospital and the Teton County school district. She made lifetime friends at both. Mary was also a very devoted catholic and an active member of the Our Lady of the Mountains community. She found love, peace, and friendship within those walls.

In 1995, after both her children had graduated from high school, Mary moved back to Pewaukee, Wisconsin, to be closer to her siblings. She continued to work in childcare until 2005.

Hanna moved to Wisconsin to live with her in 2000, where their relationship blossomed and built a love and connection only a mother and daughter understand. They did everything together, from Brewers games to Packer games and everything in between. After Hanna moved back to Wyoming, their relationship never changed, and they were partners in crime until the end.

Mary was blessed to have two best friends in her children. Her son was her pride and joy, and they were close since the minute he was born. They talked every single day, and when she moved back to Wyoming in 2020, she made sure that they had lunch or dinner twice a week.

Mary then became a centerpiece of the tribe that helped raise the love of her life, Coby Jase Peterson. They loved each other to the moon and back. They spent every other day together for two years playing, cuddling, and causing their own forms of mischief. The bond of the only grandchild and grandma that is unbreakable. Once Coby started school, they would have play dates and sleepovers; their love was unconditional.

She was a good mom. Loving and kind and fierce and strong. She put her children first and her grandson at the top. She gave as much as she could and always wanted to give us more than she had. Mary passed at home peacefully on December 17, 2025.

The Saturday before Mary passed, she got to spend time in Hoback with her family, celebrating Coby’s birthday. She even had a spotted cow! Iykyk.

She was preceded in death by her parents, Alvin and Ruth Grellinger, brothers Mike and John Grellinger, and sister Susan Arisman.

She is survived by her son, Rhett (Cherie) Koch, daughter Hanna (Justin) Peterson and her pride and joy, Coby, sister Cile Cunningham, many nieces and nephews, ex-husband Chris Koch, and seven animal grand babies.

She will be cremated and her ashes buried in Wauwatosa, Wisconsin. In lieu of flowers, donations can be made in her honor to the Alpine Library.

The family would also like to extend our deepest gratitude to her friend and neighbor, Michelle Terry.

“The best feeling in the world is knowing, your presence and your absence both mean something to someone “

~Come home good~

And as always GO PACK GO.