The intensity of Justin's scar changes from scene to scene from blood red to just noticeable.
Although Patrick Swayze has a scar under one eye while talking to President Jefferson Davis, it disappears within minutes.
After Brett receives the letter informing her of the situation at Mont Royal she looks out the window and sees troops and tents, and one tent's flap is open. A few seconds later, she looks again and there are tents missing, the tent with the flap open is now facing the opposite way, and a barrel suddenly appears.
Virgilia's hair which had been showing progressively more gray throughout the prior episodes is back to brunette with no gray.
Winfield Scott is depicted as personally commanding the First Battle of Manassas in 1861. Historically, Scott did not exercise field command, but was the overall Army commander from his headquarters in Washington.
In the foreword to Episode 1, "independence" is misspelled as "independance".
After the first Battle of Mannassas, when George Hazard is lamenting the outcome with Lincoln, he states that 28 cannon were lost, 17 of them rifled. Rifled cannon where not used until April 1862 with the bombardment and fall of Fort Pulaski near the mouth of the Savannah River.
When President Davis introduces Orry he introduces him as "Brigadier General Orry Main" but the button arrangements on Orry's uniform is that of a Major General.
During the Battle of Bull Run, troops are shown firing individually. The standard practice with muzzle loading firearms was to fire by unit.
In the summer of 1861, the gray uniform of the south was not yet in wide circulation, and most of the Confederate senior officers still wore Union blue. The series, however, depicts clearly represented blue and gray uniforms from the moment the Civil War begins.
In 1861, the United States Capitol in Washington is shown without any dome, but work on the new (and current) dome was well underway at this time, and scaffolding would have been visible, along with a construction crane.
The map on the wall in Lincoln's war room have Union troops denoted as American flags with 41 stars. At the time of the First Battle of Bull Run at Manassas, 21 July 1861, there were only 34 stars on the Union flag. At no time in its evolution have there ever been 41 stars on the US flag.
When the crowd of civilian spectators is stampeding during the battle of Bull Run, some of the female extras can be seen wearing knee socks, and not the period petticoats and long drawers that women wore in 1861.
Just before the war begins Billy Hazard tells Brett he is joining the U.S. Sharpshooters and subsequently joins the unit and fights in the First Battle of Bull Run, which occurs July 21st of 1861. In fact the Sharpshooters were not authorized until September of 1861 and did fully muster until November. Billy could not have applied to the regiment until at least two months later.
A cameraman in a light blue shirt is briefly visible after the charge of the cavalry at the first Bull Run battle.
When the Confederate cavalry charges during the battle of Manassas, a cameraman in a blue shirt can be seen for several seconds in the lower right corner of the screen (widescreen version).
In the 1st episode, when Orry meets with President Davis (when Davis and Lee fight about succession being a crime or not) a mike is visible in the mirror on the wall.
As Jefferson Davis and Robert E. Lee disagree over the Confederacy's next military move, and Davis cites Fort Sumter, a boom mic is clearly visible reflected in the large mirror at the back of the room.