The real Francis P. Church only married after the publication of the "Yes, Virginia" letter in 1897, and had no children.
The editorial was published in a September edition of The Sun, yet the movie shows it being published on Christmas eve.
In this movie, Virginia's father is depicted as a poor immigrant laborer. The real O'Hanlon was a doctor and the family was probably upper-middle class.
The movie takes place in 1897 before Oklahoma, Arizona and New Mexico were admitted as states, yet Mitchell has a map of modern America in his office.
Charles Dana was editor-in-chief at the Sun from 1868 until his death in October 1897. His son Paul was editor-in-chief from October 1897 to 1903 (Munsey's Magazine). While Edward Mitchell joined the Sun in 1875, and was on the editorial staff in 1897, he did not become editor-in-chief until 1903.