Factual error: When Benjamin is handing a store clerk some money, he is giving him a $5 bill with Abraham Lincoln on it. This happened more than 80 years before he was president. And they didn't even use dollars during the Revolutionary war. They would have used British pounds in coin form, not paper money.
Continuity mistake: Gabriel writes in his letter that his friend was killed at Elizabethtown, but you can see that the letter actually states he was killed at Monmouth.
Factual error: In one scene Lord Cornwallis' adjutant announces to Lord Cornwallis that a messenger (Benjamin Martin) has arrived. After initially dismissing the message, Lord C. pays attention on the mention of two "Great Danes" in Martin's company. The Great Dane as we know it today had many names over the centuries, but the Danish connection only became common use in the 19th century (Comte de Buffon - l'Histoire Naturelle - 1811). Until then the British would have called them Mastiffs (English or German), English Dogges, or perhaps even Boarhounds. Actually - the English Kennel Club of Britain didn't officially recognize the term/breed "Great Dane" until 1884.
Factual error: All soldiers in the Continental Army are wearing the same uniforms. Officers and enlisted men wore significantly different uniforms.
Factual error: In the scene at Lord Cornwallis' outdoor party celebration, right after Benjamin Martin and his Continental Army blows up a British Ship, one of Lord Cornwallis' Captains throws back a big gulp of his drink from his Martini glass in grief and disbelief - the problem is this movie takes place in the mid 1700s and the Martini Glass wasn't invented until the 1920s, during the Roaring Jazz days.
Visible crew/equipment: In the final battle scene where Benjamin is fighting Tavington one-on-one, the camera angle widens and shows the whole battle scene. In the bottom right corner, you can see another camera filming the action.
Continuity mistake: The beginning starts in 1776. The film ends in the year 1781 with the battle of Cowpens, a five year period. The children in the film do not age in that five years, except the youngest and that is after what I judged a six month period.
Continuity mistake: In the scene after Gabriel dies, the camera pans down from the top and you see the U.S. flag with all fifty stars, but when Benjamin leaves the tent it has only thirteen on it.
Revealing mistake: In the shot where Benjamin is riding his horse to the top of the hill, the camera pans from left to right and in the distance is the British army. But if you look to the left the trees are way too huge (a bad scale). If Benjamin had ten militamen cut one down, it would have wiped out 1/4 of the British army shown.
Revealing mistake: When Benjamin and Harry are talking on the steps of the legislature of Charlestown after deciding to go on war with the British, you can see a man behind them with something in his ear, a hearing aid or earpiece. (00:16:30)
Revealing mistake: In the shot where General Cornwallis says, "Unless I'm dreaming..." The shot is through his telescope. Notice that he's on a tall hill but the shot is almost level to the ground and it's moving down.
Continuity mistake: When John Billings, a member of the militia, finds his wife and child murdered and his house burned by Tavington's Green Dragoons, he promptly shoots himself in the head. But later in the movie, at the ending battle of Cowpens, you can see him standing in the ranks, getting shot if you look closely.
Continuity mistake: When Benjamin rides over the hill holding the fluttering flag, the flag is in his left hand. In the next shot, the flag is in his right hand, and the flagpole base is in a scabbard attached to the saddle.
Continuity mistake: When Benjamin comes down the steps out of the meeting, he walks towards his oldest son signing up. He approaches his son and his son is facing away, but they cut back to Benjamin and his son is facing him. They cut back to the son and he turns around and then back to Benjamin and it's the same shot again. His son was turned around before he turned around. (00:15:35)
Continuity mistake: In the shot where Tavington is loading his pistol (before he shoots the Rev.), he throws his ram rod, but when Benjamin's son is going to shoot him he has it back (he did not have an extra).
Factual error: The French only seem to show up at Yorktown in 1781, but they actually arrived in 1778 (the Americans would never have won if they arrived that late).
Revealing mistake: When Tavington has sliced Benjamin across the back in the final battle, Benjamin falls to his knees and the bayonet on the end of the gun he's holding, which is supposed to be metal, jiggles like rubber when the gun hits the ground.
Factual error: When Benjamin Martin and his family go to Charleston, the first view we see of the city is a shot from a hilltop, looking down on the city from the north. Charleston is a port city in the "Lowcountry" of South Carolina, a broad coastal plain. Thus, the land around the city is extremely flat, and the nearest hill of that elevation is at least 80 miles inland.
Continuity mistake: In the final battle scene, when you see the British in the distance from the Americans' point-of-view. There is a fence in the middle of the field, but when the two armies engage each other the fence disappears.