When Dorr Frank Diefendorf was born on 9 August 1874, in Canajoharie, Montgomery, New York, United States, his father, John William Diefendorf, was 27 and his mother, Emma L Keller, was 28. He married Mabel A Runyon on 15 June 1897, in Newark Township, Essex, New Jersey, United States. They were the parents of at least 1 son and 1 daughter. He immigrated to New York City, New York, United States in 1927 and lived in Newark Township, Essex, New Jersey, United States for about 10 years and Madison Borough, Morris, New Jersey, United States in 1930. He died on 13 December 1953, in Scotch Plains, Union, New Jersey, United States, at the age of 79, and was buried in Scotch Plains, Union, New Jersey, United States.
German: habitational name, apparently from a lost or unidentified place called Diefendorf. It is possible that the place in question is in fact Dübendorf near Zurich, Switzerland, which became to Diebenderf in the Palatinate (listed as a name of the Palatines), and subsequently transformed to Diefendorf, modified on the model of Diefenbach , a very frequent surname in southwestern Germany.