Lebanon, NH – Daniel Sidney Longnecker, age 94, of Lebanon, NH, died peacefully on September 18, 2025, from complications of Parkinson’s disease.
Born June 8th, 1931, Dan grew up on his parents’ small farm outside Council Bluffs, IA. He graduated from Abraham Lincoln High School in 1949. After receiving his MD from the University of Iowa in 1956, he began a career in cancer research there (1961-1969). From Iowa, he was recruited to St. Louis University School of Medicine (1969-1972), and then Dartmouth Medical School (1972-2019), where he was a full professor and eventually a professor emeritus. After a long career with nearly 200 peer-reviewed papers to his name, he published his final paper, on which he was the first author, at age 91.
Dan met Louise, his future wife, in high school. They married in 1952 and had four children. In addition to his career and family, he loved canoeing, kayaking, biking, hiking, performing arts, and museums. After his eight grandchildren were born, Dan and Louise rented an old summer camp on Lake Morey, Vermont, one week each summer, providing a wonderful venue for the family to stay connected and where important family memories were made.
In 2011, Dan and Louise moved to the Woodlands in Lebanon, NH. There Dan was a member of several committees, including the art team that oversaw placement of artwork throughout the building. Following Louise’s death, Dan’s partner was Cynthia Thompson, also a Woodlands resident.
Dan was preceded in death by his parents, Walter W. and H. Aline Longnecker of Council Bluffs, IA, and his wife Louise M. of Lebanon, NH, and his sister Ellen Lear of Council Bluffs, IA. He is survived by his children Matthew P. (Stephanie London) of Chapel Hill, NC; Daniel A. (Donna) of Bradford, VT; Jane L. Weber (Stephen) of Campton, NH; Thomas R. (Lucia) of Lincoln, MA; eight grandchildren; three great grandchildren; and his brother Walter A. Longnecker of South Daytona Beach, FL.
In lieu of flowers, please send donations to Doctors Without Borders or Northern Stage (White River Junction).
An online guestbook is available to leave Dan’s family a message of condolence by visiting www.rickerfuneralhome.com.
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