Factual error: Dominic Wingrave says "it took me 6 years to do the math." Not something any British person would say - in the UK it's always "maths."
Factual error: In Massachusetts, Atticus, Leti and George are attacked by the local sheriff and his deputies, who are patrolling the county roads. In Massachusetts, sheriffs run the county jails, but they do not (and did not) handle routine policing, which is the responsibility only of municipal police departments.
Factual error: A man enters a bank and begins firing his Glock 9mm pistol. A few of the men he shoots, jump up in the air after the rounds impact their bodies. Bullets hitting a body will never make it jump, or fly in the air. (00:00:01 - 00:01:46)
Factual error: Despite taking place in Massachusetts and many of the cars having Massachusetts license plates, none of the vehicles has the required annual inspection sticker on the lower part of the passenger side of the windshield.