Derry David Dettmer was born August 2, 1941 in Fairmont, Minnesota son of Logan and Edith (Topham) Dettmer. He attended Triumph Public Schools, graduating from Trimont High School in 1959. He entered the United States Air Force, January, 1960, his permanent base was Castle Air Force Base, Atwater, California. He married Kathleen Strohl on October 6, 1962 in Merced, California. Derry completed his college education at Fresno State University, graduating in 1972 and was employed as a State Auditor for the State of California Board of Equalization until moving to Minnesota in 1975. Derry moved with his family to Trimont, Minnesota and then to a rural farm acreage in Fairmont, Minnesota where he died. He farmed with his father and worked alongside his son, father and daughter in the family-owned tree service business.

Survivor's include; daughter Lisa R. Wimbley and her husband Dwayne of Merced, California, son Derry Todd Dettmer of rural Fairmont, Minnesota and his children, Kelvin, Drew, and Aleia and their mother, Rhonda, of Fairmont, Minnesota and daughter, Dana Dettmer and her special friend Chad Hybbert, of Welcome, Minnesota; father Logan C. Dettmer and his wife Hazel of Swea City, Iowa; sister Debra Loeschen and her husband Bruce, of Brownton, Minnesota; nephews, Jeff Loeschen and his wife, Jeanna of Minneapolis; Jason Loeschen and his wife, Jenny and son of Brownton, and Jordan Loeschen still living at home; cousins Diane Bloomquist and husband Harold, of Trimont, Minnesota Lola Warhol and her husband, Peter of Minneapolis, Minnesota; Jona Bartholomew of Minneapolis, DuWaynne Rettke and family, Hudson, Florida and Joey Midgett and family, Satellite Beach, Florida, plus other cousins, relatives and friends.

He was preceded in death by his mother, Edith Dettmer, paternal grandparents, Clara and Charles Dettmer; maternal grandparents, Mathilda and Joseph Topham, aunts, uncles, and infant brother. A special high school friend, Gail Thielhorn was always remembered by Derry. Derry was Peppo and Gail was T-Bone.