He was born April 2, 1920 (Pierpont Genealogy) and adopted by David Farwell Barnum and Huldah V. Hansen.
Excerpts from obituary, the Virginian-Pilot, Thursday, September 19, 1996: Robert F. Barnum, 76, died Sept. 17, 1996, at home. A native of New York City, Mr. Barnum retired as the secretary-treasurer of Barnum-Bruns Iron Works Inc., a company founded by his father in 1927. Following his retirement, he had been associated with Chesapeake Bay Steel as an estimator. He was a member of Immaculate Conception Mission and a US Marine Corps veteran of World War II, serving at Iwo Jima. Survivors include his wife, Ruth D. Barnum; two daughters, R. Theresa Bancroft of Cape Coral, Fla., and Roberta Boeh of Columbia, Md.; two sons, David F. Barnum of Hampton and Patrick H. Barnum of Virginia Beach. He is also survived by one granddaughter and three grandsons.