Anachronismes: The film says that news of the Battle of Little Big Horn (1876) was spread by the Pony Express - which went out of business in 1861.
Anachronismes: The calendar page that Capt. Brittles uses to mark off the days until his retirement is for the wrong month. The calendar most unusually shows the year but not the month, but it does show that the month has 31 days and begins on a Wednesday. Therefore, the only month in 1876 that this page would have fit was March. But it cannot be March, because it refers to the Battle of the Little Big Horn as having recently occurred and that Battle did not take place until June 1876. Arguably, the calendar should show the month of July, because John Wayne's character indicates that it is the 5th of the month, and news of Custer's death at Little Big Horn on Sunday June 25 would have taken about two weeks to arrive by (anachronistic) pony express.
Anachronismes: At the very end of the film the cavalry marches by with a 48-star flag. In 1876 there were only 38 states.
Continuité: Prior to leaving Fort Stock on his last patrol, Captain Brittles writes an objection to having to take a wagon on the mission. He hands the written complaint to Major Allshard, who in turn hands it to Sgt. Hochbauer, who then reads the report up side down.
Continuité: During the fight in the canteen, when Sgt. Quincannon throws the small soldier over the counter, the barman Connolly has his pipe in his mouth. In the next shot, his pipe is in his right hand.
Anachronismes: When Capt Brittles asks the Post commander's wife if the dress she is wearing is made from Top Soldier Quincanon's britches, she agrees, but the skirt is a full ankle length riding skirt made from much more material than a pair of britches.
Révélant des erreurs: During the charge, you hear the same looped recordings of war whoops over and over again. Furthermore, they are the same looped recordings of war whoops that they used the previous year in Fort Apache.
Anachronismes: Captain Brittles is retiring after 40 years in the army. It is 1876, which means he entered the army around 1836. He says he was "just a boy in blue jeans" when he entered the army. Blue jeans or denim trousers didn't come into the U.S. until Levi Strauss brought the material from DeNimes France to California during the 1850 gold rush. There were no "blue jeans" in the 1830s.
Révélant des erreurs: When Sgt. Tyree stops the paymaster's stage coach, he walks back past the horses to the coach. In the footwell of the driver's seat there are two holes through which the reins pass. The head of the stuntman who was driving the "driverless" coach is visible.
Anachronismes: As Dr. O'Laughlin is operating on Cpl. Mike Quayne, exterior views of their wagon include a modern Coleman-type two-mantle lantern, which was not available in 1876.