The recreation of the Great Land Rush involved 800 extras, 400 horses and 200 wagons. The extras were all recruited from a re-enactment society called The Re-enactors.
In Ireland, this movie has become something of a cult classic comedy for some due to the notoriously bad "Oirish" accents.
Director Ron Howard wasn't happy with Nicole Kidman's facial reaction during the shooting of the scene where her character lifts the bowl covering Joseph's (her husband Tom Cruise's) crotch. Without telling Kidman, he asked Cruise to remove his underwear. Howard got the reaction he wanted, and it appears in the film.
Three of Ron Howard's great-grandparents actually rode in the Great Land Rush of 1893, as depicted in the film.
The dress that Shannon admires in the shop window in Boston is one of the dresses worn by Clara Clayton in the last scene of Back to the Future Part III (1990).