Continuity mistake: When Boss and Charlie are crossing the flooded main street (before rescuing the dog), Boss is holding his shotgun pointing up into the rain in one shot, then in the next shot (from a different angle), it's pointing down, then up again and so on.
Continuity mistake: Near the beginning of the movie, after the rainstorm, Charlie and Mose are digging and flopping around in the mud to get the wagon out of the hole. They are both covered in mud. As soon as they get the wagon out of the hole, Button says "Here comes Boss". As Boss rides up, Charlie is removing his gloves, which are now dry and free of mud.
Factual error: In the final gunfight, we see a close-up of Charley fanning the hammer and rapid-firing his six shot Colt Single Action Army nine times in a row. [Kostner has stated in interviews that this occurs because a short scene of him switching revolvers (he had a second revolver in his belt) was left on the cutting room floor. Still a mistake, but there's the reason.]
Trivia: When the movie first opens up, you see this big green scenery with cows coming out of the bottom corner of the screen. In the widescreen version there is a cow, or bull rather, getting a little frisky with one of the cows there. It lasts for only about a second, and you can see that one of them is up a little higher than the others so it stands out.
Boss Spearman: Man's got a right to protect his property and his life, and we ain't lettin' no rancher or his lawman take either.