The script was originally written with John Ford in mind to direct. However, but Ford was busy working on Cheyenne Autumn (1964) and, in any case, wasn't interested.
Lee Marvin was Sam Peckinpah's initial choice for the role of Samuel Potts, but he wanted too much money. Marvin's agent suggested James Coburn for the part, and Coburn ultimately got the role.
At the end of the battle attempting to cross a river, one of the black soldiers is shown easily carrying the howitzer in his arms. The man would have to be very strong, as the barrel of a 12-lb. Mountain Howitzer would have weighed over 220 pounds.
When Ryan and Linda are talking to Tyreen and Dundee in the village, she has a bright red shawl wrapped completely round her, But in the shot as she and Ryan walk away, the shawl has dropped off her shoulders and is held around her upper arms.