Factual error: In the opening scene Marshal Dillon walks in Boot Hill cemetery. Dates on grave markers include 1883 and 1882. At the end of the episode Marshal Dillon and Chester discuss an Army deserter who had just been acquitted of a murder that Marshal Dillon was sure he had committed. The army deserter is being sent back to his unit to fight the Sioux and Cheyenne Indians under Gen. Custer. The viewer knows the army deserter will soon die in the Battle of Little Big Horn on June 25, 1876 - seven years before the date on one of the grave markers. (00:00:25 - 00:24:30)
Factual error: In the episode where Sydney is supposed to be in Helsinki, there are visible skyscrapers in the background. There are no skyscrapers in Helsinki.
Marco Polo - S1-E4
Factual error: The story is set in 1289, when Marco Polo was anxious to leave China against Kublai Khan's wishes, so what's Polo doing on the Pamir Plateau?
Factual error: The building shown between the stated times is located in Japan instead of the US/Washington DC as suggested by the actions in the scene. This is proven by by the Chinese characters In the Dark-gray concrete wall in the lower left side of the frame, as well as the red and blue colored circular road signs in the lower far right of the frame which are not in use in the US but in this combination unique to Japan. The street furniture, such as the road markings, the vegetation and the buildings also resemble Tokyo. (00:06:55)
Factual error: In this episode we see Blithe get shot in the neck and are told that he died in 1948. In reality he was shot in the shoulder and survived. He later served in Korea and was promoted to master sergeant as well as receiving the paratrooper of the year award. Blithe died in 1967 while on active duty in Germany.
Factual error: There is no way Laurel Lance would have been allowed on the prosecution team for Moira Queen's murder trial. Due to the facts that she both dated and as a lawyer represented the defendant's son, the defendant's daughter used to intern for her, and her boyfriend was one of the people killed in the Glades, it would have taken all of two seconds for the court to have her removed if she didn't willingly recuse herself, since her presence would be a major conflict of interest.
A New World - S3-E20
Factual error: Connor has been raised since he was a few months old by Holtz, a man with a British accent, in a dimension where there are no other humans. There is no possible way he could have an American accent, yet from the moment of his return he speaks with one.
Suggested correction: The demons in Pylea spoke English with American accents (possibly due to Wolfram and Hart's interference), and in tie-in comics, demons in the dimension Connor and Holtz went to were shown speaking regular English, though these comics were released years later.
Factual error: The verse Octavia recites is from Virgilius' poem "the Aeneid". That poem was written at least a quarter of a decade after the death of Caesar.
Factual error: In the classroom where Jack argues with Roger next to the chalkboard we can see a poster of the periodic table of the elements. We can see some elements that wouldn't be there in 1977 since they weren't discovered until 1999.
A Paige from the Past - S4-E10
Factual error: On the wall of Paige's bedroom when she was a teenager is a Metallica poster for "Garage Inc.", a CD not released until 1998 although Piper later says that Paige has gone back to 1994. (00:16:05)
The Leap Home (1) - November 25, 1969 - S3-E1
Factual error: The Post Raisin Bran cereal box sitting on the Beckett family breakfast table in 1969 has a 1990s box design. (00:18:00)
Graduation - S5-E24
Factual error: In the episode Class Pre-Union, they were the class of 2000. In the episode Graduation, they were the class of 1998.
All Prologue - S2-E6
Factual error: The police "clone" the cargo dock's computer, as though it were a cell phone, so that they can watch all the cargo traffic and see when containers disappear. In reality, to "clone" a computer would simply make an exact copy of that computer's hard drive at a specific point in time. In order to see what is happening on a specific computer in real time, it is necessary to install some sort of spyware on The Target machine.
Factual error: When Jack and Andie are talking at the dinner table about her cheating on the PSAT, Jack says, "Do you really want to get kicked out of school for cheating on something that has the world 'Practice' in front of it?" PSAT actually stands for Preliminary Scholastic Aptitude Test, not Practice SAT. This is the same mistake that Pacey made in an earlier episode.
Factual error: The car accident scene takes place in Kentucky but the state troopers are wearing the uniforms of Pennsylvania state troopers evident by the distinctive keystone arm badge.
Factual error: In the opening sequence when Maddie is supposedly driving from Michigan through Ohio and back to Pennsylvania, you can very briefly spot the reflection of a "TD Canada Trust" in the car window. This is because the show is actually shot in Vancouver. In the United States the company is simply known as "TD Bank", which doesn't operate any branches in either Michigan or Ohio. (00:01:55)
Point Blank - S2-E9
Factual error: In the scene where Mozzy is using a synthesizer to try and figure out the musical code, he starts playing random chords in frustration. Since the synthesizer is a Minimoog (a monophonic instrument) this is impossible. (00:12:45)
Chuck Versus the Fake Name - S3-E8
Factual error: When they first bring Grueber into Castle, Sara states that "he is one of five people who can hit a target from half a mile away." Half a mile is 880 yards. Basically every person who has graduated from (or likely everyone who has been selected for) sniper school in any military in the world should be able to do this. (00:05:20)
Factual error: No gearbox problem would cause the noises in the episode, it was a clutch problem.
Opening Act - S1-E4
Factual error: At the beginning, the screen shows that the year is 1988 in Corpus Christi, TX, then the camera pans into Selena and her sister eating tacos when their friend Jake arrives wearing an Arizona Diamondbacks shirt. The Diamondbacks did not exist in 1988. Phoenix was awarded a Major League Baseball expansion team in 1995 and the Diamondbacks made their debut in 1998, 10 years after this scene takes place. (00:00:30)