The 20-minute climactic fire sequence cost $150,000 to stage and burned for three days on the Fox back lot. It helped make this one of the most expensive films made at the time.
A lantern manufacturer wrote to the studio insisting that the fire must have been started by a lamp, not a lantern. They claimed a lantern would extinguish itself if tipped over, but that claim was found to be false by an experiment performed by two assistants at Twentieth Century-Fox. Soon after the fire started, the barn where the fire was supposed to have originated was thoroughly investigated, and no evidence of a lamp or lantern was found.
According to the DVD which includes the roadshow version (information given in the accompanying leaflet), Western Costumes didn't have enough costumes on hand to dress all the extras in the fire scenes and had to borrow proper period costumes from other costumiers across the country.
This was the second of 5 pictures in which Don Ameche and Alice Faye starred together. The others were "You Can't Have Everything" (1937), "Alexander's Ragtime Band" (1938), "Lillian Russell" (1940) and "That Night in Rio" (1941).
The real Mrs. O'Leary's name was Catherine, not Molly.