The McNeil family arrived in New York on 14 June 1856 via the ship Thornton. As indicated in Margaret's autobiography, their intent was to travel across the plains with one of the handcart companies that year but their plans changed when they were advised to travel to St. Louis and remain there until the next emigration season. They ended up crossing the plains in 1859. Further research is needed to identify the name of the company they traveled with.

Some sources still erroneously indicate that they traveled with a handcart company in 1856 but his brother was born at Genoa, Nance, Nebraska in January 1859.