Revealing mistake: In the battle of Little Round Top, as the Confederate soldiers are backing down the hill there is one man walking backwards and loading his gun. Behind him another soldier aims his weapon and fires, shooting the first man in the side of the head. The man then ducks and waits for the smoke from the shot to clear and continues down hill.
Continuity mistake: After Chamberlain's bayonette charge, he sees his aide wounded for a second time. The scene changes angles back and forth during their talking of how brave the boys were. An American flag is over the shoulder of the aide on close ups, but on a longer shot the flag is leaning against the tree.
Factual error: During the engagement of the 20th Maine in defense of Little Round Top there is a tremendous amount of firing going on as they repel charge after charge of Confederates. Yet, there is not a single leaf, or tree branch, that falls to the ground. With that amount of lead flying around there would have been debris everywhere. There are actual Civil War accounts where whole trees were cut in half by bullet fire.
Continuity mistake: During the sequence at Little Round Top, the same footage is used twice. The 20th Maine soldiers discharge a volley of musketry and there is a shot of a Confederate soldier being bodily flung backwards. A short time later, the Union defenders send down another volley and we see a close-up of another Confederate falling. Only it's the same actor, same footage, from a different camera about 35 feet down the Union line.
Factual error: When General Buford looks back toward Gettysburg from the cupola of the Lutheran Seminary building to see if the First Corps is approaching, the director used a colorized photograph of the town taken by Matthew Brady a few weeks after the battle to illustrate Buford's view. Unfortunately, the photo was taken from a point north of the Chambersburg Pike and the Lutheran Seminary is south of it.
Factual error: There are several scenes which show an American flag with way too many stars for that time period.
Continuity mistake: When the battle is happening at the end, the number of soldiers bodies after they have been killed varies from shot to shot. It shows them falling and dying in some shots, but the bodies are gone in later shots.
Revealing mistake: There is one shot where the camera shows the battlefield with a large tree in the middle of it. You can see that the tree has been cut away to make room for a power line, which has been removed for the movie.
Factual error: There is one minor anachronism in the scene in which several Confederate officers are discussing politics with the British officer, Freemantle, while playing cards near a campfire. General Pickett is seen holding some paper money in one hand. The only note visible is a Confederate twenty dollar bill, with the back of the note exposed. While the note appears to be genuine, the back design is unique to Confederate twenty dollar bills issued after February 17, 1864 - more than seven months after the battle.
Continuity mistake: At the beginning of the movie when the scout is talking with Longstreet, when the scout holds up his finger and says "you didn't know they were on the move out there", a long stream of troops is seen marching to the right. When the shot cuts to Longstreet then back, they have disappeared. (00:09:55)Daz
Revealing mistake: There is a scene in which Union soldiers are standing on Little Round Top. You can see the General Warren statue, which is partially hidden by shrubbery.
Continuity mistake: At the beginning of the movie it is dawn of June 30th, but should be dawn of 29th. Harrison the scout completes his task and reports to Gen Longstreet. Longstreet confers with Lee and it is now evening. The next several scenes show a new dawn when Sorrell asks if he should wake the men, Buster wakes up Col Chamberlain and a bit later Gen Buford arrives in town with his cavalry and no fighting yet. This second dawn should be June 30th, not July 1st, the first day of the battle. Further that day ends with Buford drafting report for Gen Reynolds.Historyman
Factual error: As Buford's Cavalry is approaching Gettysburg there is a scene filmed from behind as Buford stops by a fence and peers out over some fields. One of the fields appears to be a corn field and the corn appears to be about 5 to 6 feet high, much too high for June 30th in that part of the country. Having been raised on a farm in New Jersey corn that was "knee high on the 4th of July" was considered a bumper crop. The height of the corn was much higher than "knee high" on what was suppose to be June 30.
Factual error: Pickett's charge moved from west to east and was made about 2 o'clock in the afternoon. When Pickett rides down the line to encourage his men before the attack, it is clear from the shadows that the scene was filmed early in the morning.
Character mistake: Chamberlain's sidearm is a Colt Army .44, which uses a peg to secure the barrel to the cylinder axle. During the fight, Chamberlain replaces the empty cylinder with a fresh one, pushes the barrel against a log to seat it, but never shoves the peg in. A loose barrel might well result in a misalignment of that barrel with the chamber being fired, which would blow the barrel off the weapon.
Continuity mistake: There's one scene wherein Chamberlain is on the move wearing the shoulder straps of a lieutenant colonel and then, shortly later, with no explanation, on the same day, he's wearing the shoulder straps of a full colonel.