Factual error: After the birth of the baby, James Stewart and "Doc" Witherspoon are discussing the course of the war. "Doc" relates that he has always lived in Virginia and that his son died at Gettysburg at Little Round Top. No Virginia regiments fought at Little Round Top - only Alabama, Texas, Georgia, and Arkansas regiments.
Factual error: In the final gunfight in Hasting's store, John Elder fires his six-shooting Colt to a total of thirteen or fourteen times, without requiring - or doing any - reloading whatsoever.
Factual error: The El Paso newspaper is dated Monday June 15 1872. June 15 1872 was a Saturday. (00:48:14)
Factual error: The US Cavalry are careful not to run into Confederate cavalry from Fort Davis, who are shown in the distance. Fort Davis was indeed occupied by the Confederates from 1861 to 1862, but was then abandoned until 1867. The film is set in 1864, so there would be no Confederate troops at Fort Davis.