R. Lars Herseth, beloved husband, father and grandfather, as well as proud South Dakota farmer and rancher, respected public servant and agricultural leader, died of cancer on Sept. 12, 2026, at the age of 80. He passed away in his lifelong home overlooking the Sand Lake National Wildlife Refuge surrounded by his loving family.
Born June 16, 1946, in Aberdeen, South Dakota, Lars was the son of Ralph E. and Lorna B. Herseth and was raised on the family farm and ranch near Houghton. The land that shaped his childhood would remain at the center of his life for the next eight decades.
After graduating from the University of South Dakota, Lars returned to northeastern South Dakota to raise his young family and devote his life to farming and ranching—the third generation of Herseths to do so. He raised many types of crops and livestock over the years, primarily corn, soybeans and Black Angus cattle. For Lars, agriculture was a way of life; he knew many good years as well as some devastating ones due to drought, hail and flooding.
Public service was also woven deeply into Lars' life. The son of South Dakota Governor Ralph Herseth and former Secretary of State Lorna Buntrock Herseth, Lars began his own legislative career in the South Dakota House of Representatives in 1975. He went on to serve for two decades in Pierre—12 years in the House and eight years in the Senate. During those 20 years in the South Dakota Legislature, Lars became one of the state’s most prominent and respected legislative leaders, serving eight years as House Minority Leader from 1979-1986, President Pro Tempore of the Senate in 1993-94, and Senate Minority Leader in 1995-96. He was also the Democratic nominee for governor in 1986.
During those years, Lars was known for his legislative acumen, command of the issues, collegiality that knew no partisan bounds and being true to his word. He was exceptionally fair-minded and a steadfast advocate for women’s rights and Native American issues. During his final legislative term, he spoke passionately in opposition to a bill that sought to prevent recognition of same-sex marriage.
Lars was particularly engaged in issues affecting agriculture, transportation, economic development and healthcare. His approach to public life was to put solving problems for the people of South Dakota ahead of political differences. Few issues demonstrated that conviction more clearly than South Dakota's railroad crisis of the late 1970s and early 1980s. As abandonment of rail lines jeopardized the state’s transportation infrastructure and agricultural economy, Lars worked with Gov. Bill Janklow and legislators of both parties to preserve essential rail service.
Following his years in elected office, Lars remained deeply engaged in agriculture, public policy and civic life. He served in leadership roles supporting corn producers and renewable fuels, including as president of the American Coalition for Ethanol and as a member of the South Dakota Corn Utilization Council. His advocacy reflected his belief that agriculture, innovation and homegrown energy could strengthen rural communities, the state's economy and national security. His effective leadership and significant contributions were recognized by multiple organizations, including the South Dakota Corn Growers Association's Excellence in Agriculture Award and the American Coalition for Ethanol Merle Anderson Award.
Yet the public record tells only part of Lars Herseth's story.
For the past 32 years, Lars was married to his loving and devoted wife, Diane, who shared his affection for the land, the rhythms of planting and harvest and the stunning visual and auditory gifts of Sand Lake and its wildlife. They also shared a passion for horses. Lars raised quarter horses in the 1970s and ’80s, and when Diane came into his life, he not only taught her to ride, but they also traveled extensively to follow high-profile thoroughbreds at premier racetracks across the country. They also visited nearly two-thirds of America’s national parks, experiences that reflected Lars’ appreciation for our nation’s natural beauty and history as well as our shared commitment to preserving these remarkable places.
Lars raised and cherished his three children — Todd, Stephanie and Matthew — demonstrating extraordinary love and support, providing wise counsel and guidance, making them laugh with his great sense of humor and expressing his pride in their work ethic and accomplishments. His three grandchildren—Addison, Ayson and Zachary—also brought him great joy, especially when they were exploring everything the farm and ranch had to offer. With the older two grandchildren, Lars and Diane enjoyed many adventures and instilled in them a profound appreciation of the natural world. With the youngest, they marveled at his musical talent on the violin and piano and treasured the opportunity to see him conduct an original composition for chamber orchestra performed in the State Capitol last December.
Three other family members were also his closest friends — elder sisters Karen and Connie and cousin Marc, who was more like a brother since childhood. Their memories became the stories all the nieces, nephews and cousins wanted to hear at every holiday gathering at the Herseth Ranch. Lars and Diane loved spending time with extended family in Pierre on the banks of the Missouri River. The tradition of Thanksgiving at Kabekona Lake in the Northwoods of Minnesota over the past two decades also was particularly meaningful.
Those who knew Lars will remember a man deeply rooted in a particular place, connecting him to the generations who came before in stewarding the land. They will remember his intelligence, kindness and wit, his knowledge of agriculture, ethanol and politics, his optimism, courage and independent spirit, his loyalty to friends and neighbors and his deep love and affection for his family.
Lars is survived by his beloved wife, Diane Friedman Herseth; his grateful children, Todd Herseth, Stephanie (Max) Herseth Sandlin, and Matthew Anderson; his beautiful grandchildren, Addison Anderson, Ayson Anderson and Zachary Lars Sandlin; his dear sisters, Karen (David) Herseth Wee, Connie (Jerome) Jacobs; his trusted cousin, Marc Herseth; and his adoring nieces and nephew, Mari, Allix, Calli, Rebecca and Jonathan.
He was preceded in death by his parents, Ralph E. Herseth and Lorna B. Herseth.
A memorial service will be held 2 p.m. Sunday, Oct. 4, in the Johnson Fine Arts Center, Northern State University, 12th Ave. SE, Aberdeen.
Memorials may be directed to Feeding South Dakota or South Dakota Public Broadcasting.
Celebrate a life with the whole community in The Dakota Scout. Contact [email protected] to have your loved one remembered today.
