Revealing mistake: During the Little Bighorn massacre one of Custer's lieutenants turns to address Custer and is struck in the back with an arrow, and the thick pad or board is visible under the actor's shirt.
Continuity mistake: In the scene where they ride to the top of a hill on horseback, you can see a white van and power lines in the distance.
Other mistake: When Kirk Douglas 'appears' to pull a knife from his collar and throw it into Lee Van Cleef's chest, you can see Kirk pick the knife up from a trough in the front edge of the bar. The knife is already in his hand when he reaches to pull the knife from his collar.
Continuity mistake: After Jack's second horse never comes back, neither do Ben's shoes. Were they with the horse that we don't know what happened to?
Suggested correction: The shoes are purposely removed and never seen again, as is the horse, by Jack. This is mentioned by the Indian tracking them.
Revealing mistake: During the shoot out with McGivens's gang at the Cortez ranch, the wife of Cortez sneaks out of the trap door with her baby and peers around the side of the building. You can notice that the baby is really a doll.
Continuity mistake: When Luz is talking to Jet on the phone for the first time, from the front she's fiddling with the phone cord with her left hand. When it cuts to the reverse, however, her hand is flat on the desk.
Factual error: After they bury Jack's father, the stage driver hands Jack what he refers to as a "Navy" Colt. However, in 1841, the only colt handguns were a handful of Paterson revolvers, usually carried by Texas Rangers, and in fact, the revolver handed to the boy was a cartridge weapon.
Deliberate mistake: At the beginning of the movie Mr. Coates tells his wife that he will be gone "all of three months, maybe four." The first time we see Bud and Elizabeth Searcy she tells Travis that her dog is pregnant and that Old Yeller is the father. We then see her dog that does not look very pregnant. The next time we see Elizabeth she presents Travis with one of the pups. The problem is that the pup that was supposedly just born is about 4 months old.
Continuity mistake: When Paris has his private meeting with Woodward, he's smoking a cigar and you can see smoke rising all around him. The camera angle changes to a wide shot and all of the cigar smoke is gone.
Continuity mistake: When Levoi and Crowhorse visit Grandpa for the first time note the white and black beaded belt on the table behind Grandpa. In the beginning it hangs at the edge just at the first black stripe. Just after Grandpa trades Levoi for his glasses and hands him the rock, the belt now hangs nearly to the second black stripe. After that cut the belt now hangs in its original position. (00:37:30 - 00:38:30)
Deliberate mistake: When Raza is chasing the "empty" train, as it goes over the trestle just before he stops it, you can see the engineer in the train's engine.
Continuity mistake: In the trailer, there is a scene showing Matt Damon in a fight. The other person pulls out a knife and cuts Damon on the right side of his face, leaving a big scar. In the next scene of the same commercial the scar changes from the right side of his face to the left side and then back again.
Factual error: The narrator mentions that the Cheyenne tribe split in half in northern Nebraska. The scenery would suggest otherwise, as there are no mountains that high in Nebraska.
Factual error: Somewhat late in this German made western, Lex Barker and company are led into an Indian village, somewhere in (I presume) the Rocky Mountains. You will notice that there are at least two totem poles in this village. The kind of Indians shown dress like Plains Indians, and not like Northwest Indians. Northwest tribes who are found in Washington state, USA, and British Columbia, Canada, are the only tribes with totem poles. Plains Indians did not have totem poles.
Continuity mistake: The third time we see the stagecoach on its way to Denver, it's passing the exact same tree and hill that it passed at the start of its journey. It's also traveling on a paved road, which in 1860s frontier Colorado is extremely unlikely. (00:11:15)
Continuity mistake: Sacajawea (Donna Reed) dives into the water to retrieve some important maps, which have fallen in and been taken to the back of the boat. When she dives in, the maps are back to the original area they fell into, when they should have been quite a distance from where they landed in the water.
Audio problem: When John Wayne has his back turned and tells the newspaper man "print that and he will kill you sure as hell", you can tell by the side of John Wayne's face that he isn't really saying anything.
Visible crew/equipment: In the last scene, when they are riding alongside a river, shortly after the harmonica player changes songs, there's a closeup of John Wayne and appearing from the right on the other side of the river, a pickup truck appears, and then they quickly cut to different characters. (01:56:55)
Continuity mistake: Near the end, Sam Clayton is nearing the finish. The audio leads you to believe that the horse is breathing VERY hard, but when the camera shows the horse, the nostrils are NOT flared as they would be on a horse that has been run to exhaustion (or even down the block). Also, the people filming this scene obviously have no clue about the nature of sweating in horses. They showed "lather" all through the horse's mane. The ONLY places horses will lather while sweating is where something is rubbing, i.e. underneath the saddle, the bridle or breast collar, where the reins rub on the neck or between their back legs.
Factual error: While the Confederate captain is explaining the mission, a couple of the "patriots" are inserting cartridges into their Colt Peacemakers. A neat trick, since the Civil War ended in 1865, and the Peacemaker wasn't introduced until 1873.