Goofs

Slade loses his glasses during the cliff scene. They mysteriously reappear soon after.

When Junior Ferguson jumps off the cliff into the water after Harlow falls, he hits the water mostly on his back. When the camera cuts to the crowd above and then back to the water, his feet are sticking up out of the water, implying that he'd gone head-first into the sandbar.

After Harlow wins the fight with the General, Belle puts Harlow's hat back on his head. When the camera angle changes, she is still holding Harlow's hat.

While Slade sets up the dynamite on the bridge, Harlow starts across it twice.

At one point early on the trip, Phil and Harlow discuss the fact that more wagons have joined their five, referring to a later plot point in which other settlers have decided to join the migration back east. This seems to be edited out of sequence because the next time the whole trail is depicted, there are again only the five wagons from the start.

While Harlow and Larchmont are fighting, the camera cuts to, among other events, a woman giving birth. The baby is withdrawn from the womb without an umbilical cord.

Julian fires his warning shot into Slade's belly, turns, and walks away. Then he fires 12 more times without reloading, for a total of 13 shots. That would be impossible with two 6-shot revolvers.

Near the end of the movie when the politician is making a speech encouraging the attendees that their future lies in the west, he gestures and points with his cane indicating the direction west. However based on the time given, high noon, (as indicated by the watch of the man with the starting pistol), the shadows on the ground clearly indicate that he is actually pointing east.

The second scene of Harlow picking up a bottle and pouring the remaining bit of liquor out of it, is clearly re-used of his first one. (this was done due to John Candy's real-life death).

According to the movie, the land rush occurs during Ulysses S. Grant's presidency, which ran from 1869-1877. However, it shows a Pony Express rider delivering a message to Slade. The Pony Express existed from April 1860 to October 1861.

During the fight with the General, a contrail is clearly visible above Harlow's head.

Model trains such as those seen in the film did not exist until after World War II.

When the girls are sitting around the fire, sewing and discussing Belle's line of work, a studio monitor (or similar light source) is reflected in Henrietta's glasses.

When they find out the cavalry is coming, they are supposedly close to St. Louis but there is a palm tree in the background.

After Harlow and Larchmont are done fighting, Julian refers to Harlow as "James Aloysius Harlow." The character's name is "James H. Harlow", as written on his telescope and mentioned by other members of the wagon train.