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.
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.
Factual error: All soldiers in the Continental Army are wearing the same uniforms. Officers and enlisted men wore significantly different uniforms.
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: 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).
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.
Factual error: During the evening at the beach scenes, the sky over the sea appears as though it is during sunset. In the morning, the sunrise is in the same direction. A South Carolina beach would only face toward a sunrise.
Factual error: Although the historical advisor for the film is The Smithsonian Institute it does not seem to have noticed that the toy soldiers used in the film (some in superb close-up} are all dressed in uniforms of the mid to late 19th cent., i.e. approx. 100 years later than when the film is set.
Factual error: In the scene where the Martins are leaving Charlestown to go to Santee, they are actually travelling south toward the west Ashley area of south Carolina. If they were actually travelling to Santee they would be heading northwest with Charlestown directly behind them.
Factual error: When Benjamin is trimming bullets he makes from toy soldiers, the tool he uses to trim them has a manufacturer's stamp on the handle, not something that should be there in this time period.
Factual error: Mel Gibson's son has toy soldiers from the future. In one shot when he is melting one of the soldiers it is visible. Although it has a red uniform it isn't a British soldier. In fact it depicts Hofburg Trabanten Leibgarde which was the personal guard of the sovereign originally from Austria, in uniform from around 1850 - 1918. (01:10:55)
Factual error: Throughout the film, all the women are running around without "modesty pieces," a scarf/shawl that would cover their shoulders and tuck into the front of their dress, so their breast tops were not exposed.
Factual error: French navy officers arriving at Yorktown to bomb the city are wearing tricolor roundels on their hats. This is historically impossible as the three colours blue white red representing France is a result of the French revolution that took place later in 1789. Before the revolution, the flag of France was just white with the symbol of the king.
Factual error: Gabriel claims that Charlston fell to Lord Cornwallis, however the town fell to Sir Henry Clinton, as Benjamin Clinton surrendered it to him after a little over a month long siege.