David was married to a wife whose name is not known.
From the Binghamton Press, Tuesday, November 6, 1928: David E. Barnum, 79 years old, member of a widely known Broome County family and active in local business and fraternal circles for many years, died at the Binghamton City hospital this morning. Death was caused by gland trouble from which he had suffered since last Labor Day, being confined most of the time to the hospital.
Mr. Barnum was for 25 years a leading grocer with place of business on Chenango Street until his retirement about 10 years ago. He was born at Barnum Hill in the town of Union two miles northwest of Choconut Center, and was the son of Enoch Barnum, a widely known farmer of that section. His brothers were Byron C. Barnum, still residing at Johnson City; the late Hiram Barnum, for years the head of the Binghamton Board of Education, and the late Loring H. Barnum, for many years a leading Binghamton fire insurance man. He attended the rural school near Barnum Hill and later the old Binghamton Academy in this city.
Mr. Barnum is survived besides his brother, Byron C., by a nephew, Howard Barnum of this city and five nieces: Mrs. H. J. Crawford, Middletown, Pa., Mrs. Oscar Stewart, Johnson City; Miss Mary A. Barnum of Pierce Creek; Miss Helen Barnum of this city and Miss Agnes L. Barnum, teach in the high school at Greenwich, Connecticut.