Factual errors: The 1935 Wiley College debate team did not take on Harvard; they actually debated USC. According to a Denzel Washington interview, some artistic license was taken since Harvard had a better reputation.
Continuity: When Henry Lowe comes home drunk after viewing the lynching, he and James Farmer Jr struggle. The lamp constantly changes between upright and knocked over.
Continuity: After attending the late-night union meeting, when James Farmer Jr. comes home, he takes off his shoes so he can be quiet. Even though he has run through the woods, water, and mud with Mr. Tolson to escape from the police, his pants legs are clean.
Anachronisms: In the final debate against Harvard University, James Farmer Jr. was seen getting up to the hot seat, clicking a ballpoint pen closed. This movie was set in 1935, while the ballpoint pen wasn't patented until 3 years later, in 1938.
Anachronisms: When Prof. Tolson lectures his students about the origin of the word "lynching," he is referring to the so-called Willie Lynch Letter or Willie Lynch Speech, which is widely believed to be a contemporary hoax. There is no historical or archival record of it prior to the 1990s (when it began to appear on the Internet), so a 1930s professor could not cite it.
Factual errors: In the scenes of the train, the order of the cars is wrong. The combine is placed between the coach and the observation car, with its baggage compartment to the rear of the train. James Farmer Jr. is shown running from the coach to the observation platform as the train leaves the station. This would not be possible as he would not be allowed through the baggage compartment with the train in this configuration. Common practice was to place the combine at the front of the train with its baggage compartment oriented toward the front of the train.
Factual errors: Marshall, Texas was a larger town in 1935 than portrayed in the film. It had been a major rail center since the 1870s, not the one-track whistle stop in the scene at the train station.