When Jacob Whittaker McNail was born on 13 June 1849, in Missouri, United States, his father, Benjamin McNail, was 34 and his mother, Susanah Emilie Stout, was 33. He married Claudia Browning on 8 April 1877, in Boone, Arkansas, United States. They were the parents of at least 1 son. He lived in Pilot Knob, Iron, Missouri, United States in 1900 and St. Louis, St. Louis, Missouri, United States in 1920. He died on 1 October 1922, in Missouri, United States, at the age of 73, and was buried in St. Francois Township, St. Francois, Missouri, United States.