James “Jim” Joseph Siemonsma, age 86, passed away peacefully on May 24, 2026, at the VA Hospice Cottages in Sioux Falls, South Dakota. He was born on August 15, 1939, in Rock Valley, Iowa, to Bernard and Dora (Van Whye) Siemonsma.
Jim graduated from Colton High School in Colton, South Dakota, before proudly serving in the United States Army as a Field Artillery Intelligence Specialist, including service in Alaska. His military service reflected the quiet strength, discipline, and dedication that would define the rest of his life. In 1965, he married the love of his life, Mary Jo Christiansen, beginning a remarkable partnership built on faith, love, loyalty, hard work, and deep devotion to family.
Raised on a farm, Jim learned the values of perseverance, responsibility, and grit. He carried those values throughout his life and became known for his steady presence, strong character, and willingness to help anyone in need. Jim spent 46 years with Sioux Valley Energy in Colman, South Dakota, a career built on the same reliability and quiet dedication he brought to every part of his life. During much of that time, he was also farming, though he preferred to call it his “hobby farm,” a description that greatly understated the work involved. The combination said everything about who he was: a man who didn’t consider hard work a burden, who found meaning in keeping things running, whether the lights stayed on for a rural community or the livestock were fed before dawn.
Jim and Mary Jo shared 59 wonderful years of marriage. Together, they built a home grounded in faith, strong values, family traditions, laughter, and unconditional love through every season of life.
He was the proud father of seven children and cherished every moment spent with his many grandchildren and great-grandchildren. Nothing brought him greater happiness than family gatherings filled with stories, laughter, card games, meals, and memories that will live on for generations.
Jim believed one of life’s greatest responsibilities was providing for and guiding his family. He could be tough at times, but he was always fair, thoughtful, and intentional. Everything he did had purpose, whether teaching lessons through hard work, quietly offering guidance, fixing what needed fixing, or simply showing up when it mattered most. Beneath his strong exterior was a deeply caring man whose greatest pride and joy was the family he and Mary Jo built together.
Jim found peace and happiness outdoors, especially while fishing on the Missouri River and during treasured trips to a remote fishing camp in Canada. He loved the rugged beauty and quiet solitude of being completely off the grid, surrounded by wilderness, water, family, and friends. The rustic camp became one of his favorite places, where he enjoyed tinkering with projects around camp, working with his hands, and embracing the simple life far from the noise of the world. After retirement, he and Mary Jo also loved spending time in Arizona, enjoying the warmth, beauty, and slower pace of life.
Jim will be remembered for his quiet wisdom, deep Catholic faith, strong values, tireless work ethic, sense of humor, and complete devotion to his family. His legacy of love, strength, generosity, and integrity will forever remain in the hearts of all who knew and loved him.
Jim is survived by his seven children: David (Michelle), Charles (Silvia), James (Jana), Julie (Randy) Weller, Steven (Angelique), Paul (Christina), and Regina (Stephen) Guinn; twenty-six grandchildren and fifteen great-grandchildren; many nieces and nephews; and countless close friends, especially those from Butterfield RV Park, whom he loved as extended family.
He was preceded in death by his beloved wife, Mary Jo (Christiansen) Siemonsma; his parents, Bernard and Dora Siemonsma; his sisters, Berneith Baumberger and her husband, Verne, and Mary Alice Eichler, and her husband, Frank; and by his brothers, Harold and his wife, Magdalen, and Robert and his wife, Henrietta.
Visitation will be from 5-7 PM on Thursday, May 28th at Rustand-Weiland Funeral Chapel with a Rosary at 7 PM. The Requiem Mass will be at 1:30 PM Friday, May 29th at Rustand-Weiland Funeral Chapel with Father Paul Baumberger officiating. Visitation will be one hour prior to Mass. Burial will be in St. Thomas Cemetery with military honors provided by Madison American Legion and Madison VFW along with active US Army personnel.
In lieu of flowers, the family, honoring Jim’s wishes, requests charitable donations be made to Immaculate Heart Seminary, P.O. Box 56, Round Top, New York 12473, or The Daughters of Mary, P.O. Box 205, Round Top, New York 12473.
