Continuity mistake: In the scene where the postman gallops by the country house full blast and then comes back to pick up the letter from the boy's hand, you hear hoof sounds for long enough to take him hundreds of metres away, while the camera is on the boy. But when he is actually shown stopping to turn his horse around he has only come as far as the corner of the premises, maybe 20 meters away. (01:53:05 - 01:54:05)NancyFelix
Trivia: The pony girl was Costner's daughter. The boy of the letter (Postman's horse stunt) was Costner's son.
The Postman: Uh... Strangers... I hate this. Do they want to share what they got or take what you got? Do you say 'hi' or do you blow them away?