Goofs

When Anna Surrat takes pieces of broken glass out of the window, the shot from Aiken's point of view the window shows an intact window.

When Mary is being prepared to hang she is shown having her hands tied behind her back carrying her rosary. The next shot, when her daughter is observing, she is shown with her hands in front of her. The last shot shows her legs being tied with her hands secured behind her again.

When Booth is trapped and killed, he still has his distinctive mustache. He shaved his face soon after he killed Abraham Lincoln, to make himself less recognizable.

When Secretary of State William Seward is stabbed in his bed, the room is shown as being brightly lit. According to historical accounts, though, the room was quite dark, which accounts for Lewis Payne's failure to kill Seward; he missed hitting any vital areas with his knife because he simply could not see his target very well in the dark room. In addition, the elderly Seward was very thin, almost literally 'all skin and bones,' which caused Payne's thrusts to miss their mark.

When Aiken first meets Mary Surratt, she asks him how old he is, and he says he is 27. Aiken was born in September 1832, which would make him 33 at the time of Lincoln's death.

When the convicted are hanged at the film's conclusion, it's shown that all died instantly from the drop. According to witnesses and even confirmed by Alexander Gardner's photographs, Lewis Payne (AKA Lewis Powell) survived the fall. Payne was a stout, strong man with a huge slab of neck muscle. In the initial post-hanging Gardner photographs, Payne's bound and restrained figure is seen blurred as he struggles, before dying of strangulation.

The assassination attempt of William Henry Seward is almost totally incorrect. A servant met Lewis Powell, who was pretending to bring Steward medicine, at the door and tried to stop him from entering. Fred told Powell to come back later because his father was asleep. Fanny, who had dark haired, opened the door to tell Fred that their father was awake. Fred closed the door on her and turned back to Powell, who shot at his head. The gun misfired and he bashed Fred's skull in, leaving a hole and exposing his brain. Powell entered the dark room and shoved Fanny aside as she tried to stop him from attacking Seward. He began stabbing Seward, whose jaw splint deflected the blows somewhat, saving his life. Seward managed to roll off the bed and under it before losing consciousness. Gus and the soldier nurse entered and fought with Powell, who stabbed both about 7 times each before fleeing the scene.

When Aiken visits Mary in her cell, she recites a verse from the bible. but they get the book wrong. she says "Proverbs," but the verse she recites is in the book of Psalms; Psalm 139:23-24.

The locomotive has a modern automatic coupler. Its predecessor, the Janney or Buckey coupler, was patented in 1873.

One character says that Mary Surratt should be shown clemency "because of her age and gender". The word "gender", until the very late 20th century, was only a term used in grammar assigning a masculine, feminine or neuter association to a noun. The speaker would certainly have used the word "sex".

In the film, the conspirators are kept in a prison miles from Washington. They were actually held in the Old Capitol Prison, the site of the current Supreme Court, in the center of town.

The actors from "Our American Cousin" are locked in a cell at the Washington Arsenal Prison, but we're never told why. They are witnesses, not criminals.

One of the characters calls Aiken "Frederick Sebastian Aiken". His middle name was 'Augustus'.

Anne tells Aiken her brother's room is upstairs on the left. He goes upstairs and makes a right into the room. From the camera angle it is on the left, but from Aiken's perspective it is on the right.