Jens was married to Mette Magdalene Johansen (a widow of Christen Jensen Skov) in Seest Village, Vejle County in 1867. He was the illegitimate son of Jensine Clemmensen conceived by an affair with a married neighbor, Jens Jensen, and was born at Korning Village, Denmark. Mette died and is buried in Denmark. Jens emigrated to America in 1874 leaving his three oldest children at the Work House(Children's home) Langskov in Vejle amt). The youngest child lived with Kirsten Andersdatter, age 60, and her daughter, Sanne Kristensen, age 40, in Vejle, Nørvang, Uldum. In November of 1883 Jens had saved enough money to have them come to America.

Christine Henningsen came to America with Jens and they were married 5 days after their arrival in 1874 and settled in Sheffield, Illinois for 5 years and then went to Elk Horn, Iowa. Jens and Mette's four children were Christine "Sine" who married Jacob Peterson, Elk Horn, IA and died in 1955; Marie Sopphia "Sophie" who married Hans Peter Hansen, Harlan, IA and died in 1934; Johannes Christian "John" (later changed to Kyar) who married Ellen Mason and died in 1927; and Jens Christian who married Caroline Johnson Carlsen, Detroit, MI. and died 1943 at Eloise Detroit, Michigan.
Jens and Christine had five children: 1)Henry Lauritz who died at the age of 27 of stomach cramps; 2)Emma who married Rasmus Jorgensen and died in 1884; 3)Anna Dorthea who married Andrew Jorgensen and died in 1963, 4)Hans Emil born in 1879 and died in 1967 and 5) Frederick Clemmensen born in 1881 and died in 1955. Fred was a long time sheriff in Audubon County and was in one unsuccessful attempt to capture Bonnie and Clyde.

Jens Marriage certificate to Mette states his day of birth is the 25th and his obituary has the 23rd.

Jens had three sisters: Inger Marie (F.A.G. #6339760) , Metta Sophia (F.A.G. #41490019)and Mette Marie (F.A.G. #158559936) .