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.
Three of Ron Howard's great-grandparents actually rode in the Great Land Rush of 1893, as depicted in the film.
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.
Although dialect coach Tim Monich had over 17 years of experience, this film was the first time that he had to teach his cast to speak in an Irish accent. Technically, Nicole Kidman's accent is incorrect. As a well-to-do landowner's daughter in Ireland at the time, she would have spoken with a largely English accent. That probably would have confused international audiences, so she was taught to speak in an educated Dublin accent.