Continuity mistake: In the flashbacks seen at the start of the film, Charles Nichols introduces Kimble to Alec Lentz. When this flashback is revisited later in the film, when Kimble breaks into Frederick Sykes' house, the words and actions of Nichols and Lentz are slightly different to what was seen earlier in the film.
Continuity mistake: Kimble dives from the top of the dam when Gerard traps him in the tunnel. But in wide shots of Kimble falling, there's no tunnel above the dam. (The tunnel scenes were shot in Chicago, but the location sequences were done at Cheoah Dam in North Carolina - which has no tunnels.).
Visible crew/equipment: During the chase scene in the access tunnels under the dam, there are several shots where the camera is in front of Harrison Ford moving backwards, showing him as he runs from Tommy Lee Jones. You can see the tracks that the camera dolly is riding on.
Continuity mistake: During the scene in the dam tunnels, Kimble holds Gerard at gunpoint. In the first close-up, Gerard has three strands of hair that are all apart from each other. The shot cuts to Kimble and back to Gerard, and the strands are all together. Then it goes back to Kimble, who says "I didn't kill my wife." When it goes back to Gerard again, the strands are apart once more. We know he couldn't have moved them because he has his hands up. Later, when Gerard is holding up Kimble at the tunnel opening, there is only one strand on his forehead.
Revealing mistake: When Dr. Richard Kimble is nearly run over by the freight train, look closely at the axles of the locomotive passing overhead. Diesel locomotives have large electric motors on each axle that actually propel the train. These electric motors are missing which would be similar to a car without a transmission. There is no way for a locomotive to move under its own power without these electric motors.
Other mistake: When Dr. Nichols hits Dr. Kimble with a chair, look carefully. As Dr. Nichols swings the chair, it starts falling apart before it even makes contact with Harrison.
Revealing mistake: When Kimble jumps from the dam, the falling body is clearly a dummy, otherwise he broke every single bone in his body before he even jumped.
Continuity mistake: When Richard Kimble comes back to the hospital and is seen by the nurse, they embrace. There is a shot with him facing the camera immediately followed by a shot of her facing the camera. Their arms have somehow magically changed positions from the original embrace.
Factual error: When Dr. Nichols leaves the damaged elevator, and Kimble later exits (the infamous arm in the door shot), neither would be possible as the elevator was emergency stopped by Nichols and can be seen positioned just below the floor. The elevator doors would not line up with the floor doors, and both sets would need to be manually opened.
Character mistake: After Kimble jumps from the drain pipe over the waterfalls, the scene goes to Gerard standing in the pipe telling his crew to leave, then they all leave without picking up Gerard's gun that Kimble threw down next to him.
Deliberate mistake: The dummies are obvious when the jail bus is flipping over onto the railroad tracks.
Continuity mistake: The scene in which Kimball in Cook County Hospital takes Joel to the lift starts with Kimball looking at the boys chest x-rays. In the first shot Kimball is looking at the front side of it and in the second shot (with camera looking over his shoulder) at the back-side but he does not let the x-ray out of his hand between the shots.
Factual error: During the car chase that leads to the tunnel, there are several freeway signs pointing to Murphy, North Carolina, and the film is set in Chicago.
Continuity mistake: Just before Harrison takes his leap from the pipe in to the dam, Tommy Lee Jones tells him to put his hands up. When Ford puts them at head height, Jones then tells him to put them above his head. Ford does this from the far out shot, but when there is a close-up of his face, his hands are at head level. This occurs in a fraction of a second so there was no chance for him to move them.
Factual error: In the scene on the El where the cop gets shot, you can hear the train engineer saying, "Balbo, next stop"; this is also said later on the police radios, when they say there is an officer down at the Balbo station. Two problems: 1) There is no Balbo station. 2) Even if there were, the station they start from is at Lake street (looks like the main transfer station at Clark and Lake), and the train pulls out going north. However, Balbo is south of Lake street.
Continuity mistake: After Kimble escapes from the prison bus moments before it's demolished by a train, he steals an ambulance, is chased through the mountains by a police helicopter, is trapped in a tunnel, escapes by crawling through a drain and jumping from a very tall dam into a raging river. A very thrilling sequence, but he's supposed to be in Illinois, where there is no terrain remotely resembling this.
Plot hole: When Kimble is heading towards the dam driving the ambulance in the tunnel, his lane is empty in the wide angles, yet in the close-ups he is swerving the steering wheel violently as if there were cars ahead. This keeps changing back and forth. It adds up for tension, but it is totally ludicrous.