When Texas Ranger Frank Hamer was earlier portrayed by Denver Pyle in Bonnie and Clyde (1967), he was characterized as an incompetent fool, prompting his widow Gladys to sue Warner Brothers for defamation of his character. In 1971 an out-of-court settlement was reached.
Kevin Costner was offered the role of Frank Hamer ten years earlier, but turned it down because he felt himself too young to play a grizzled, retired lawman called back into service. Having gotten older he felt the role was a better fit, though he still decided to gain 15 pounds to give himself a more over-the-hill appearance.
The quest for historical authenticity prompted director John Lee Hancock to recreate the ambush/death scene at the actual location where it had occurred Wednesday May 23, 1934, just outside Sailes, Louisiana, in the rural Bienville Parish.
Kathy Bates portrays Miriam "Ma" Ferguson, the first female governor of Texas. Ferguson's husband had previously been governor of Texas, but was impeached and convicted on embezzlement charges. Ma ran as a puppet candidate, making it clear her husband would be calling the shots, and she was every bit as corrupt as her husband had been. She was defeated after her first term but was elected again six years later. When first elected, about 40 Texas Rangers resigned instead of serving for a woman governor. Most of them found law enforcement jobs in other capacities. Ferguson then fired the remaining Rangers.
When Bonnie Parker limps away from the car at the beginning of the film, this is historically accurate as she'd injured herself earlier in a car accident when Clyde drove their Ford V-8 off a bridge into a dry riverbed where the damaged battery leaked acid over Bonnie's left leg causing her third-degree burns. Her injuries were so severe she walked with a limp for the rest of her life.