All-Star Cast: Though more of the Hey, It's That Guy! character actor variety than the A-list star variety, although Daniel Day-Lewis, Sally Field, Tommy Lee Jones and Joseph Gordon-Levitt definitely all qualify.
Spielberg has been researching for this film for 12 years, down to the correct wallpaper and books in the White House of 1865 and the right ticking noise for Lincoln's watch (Recorded from the actual one!)
Fake Brit: Lee Pace as Fernando Wood (the real Wood was completely American.)
He sounds that way because he is using elocution, the art of formal speech. Wood may have learned this "classical" sound in school, or picked it up by listening to actors (perhaps the extremely popular Booths) and others trained in public speaking. Bill Raymond as Schuyler Colfax, saying "The House recognizes Fernando Wood," is also using it. Some film actors still practiced elocution in the 1960s.
Life Imitates Art: This film led to Mississippi officially ratifying the 13th amendment 150 years after it passed. To explain, after seeing the movie, Dr. Batra of the University of Mississippi and his colleague Ken Sullivan were interested in the history of the amendment and found to their surprise that Mississippi's vote was missing from the national record. Sure enough, it turned out their vote had never been sent to the US Federal Register, though the 13th had long become common law in the state. They wrote to their congressmen to correct this error, and February 7th 2013 Mississippi officially ratified the 13th Amendment.
Method Acting: A rare director self-enforced case. Steven Spielberg eventually started addressing his principal actors by character name while on set, and even took to wearing a suit while filming so he didn't clash with the scene.
Old Shame: Has been an audience reaction during the voting scene; if they're from a state that had congressmen who did not vote yea, a groan can be heard in the theater (unless you're from Connecticut, in which case you'll be mad that the movie shows two House members voting against the amendment when in Real Life all four were in favor of it).
Playing Against Type: Sally Field, who normally nowadays plays sweet, [grand-]motherly types, as controlling, bitter, mentally unstable Mary Todd Lincoln.
While he's certainly played heroic characters before, Daniel Day-Lewis' turn here is generally subtler than some of his more recent work in There Will Be Blood and Gangs of New York.
Reality Subtext: Daniel Day-Lewis and Sally Field had only met in passing prior to this film. Mary's and Lincoln's relationship is fraught, to say the least; however, over the course of filming the two actors quickly came to adore each other.
The great-grandfather of Michael Stanton Kennedy was a newspaperman from the town where his character, Hiram Price, lived. When filming the scene where the 13th Amendment passes, Kennedy started to cry and couldn't explain why until later, when he told Steven Spielberg "We're in this room recreating one of the most important moments in American history... and up there [in the balcony] with the press sat my great-grandfather."
Hey, It's That Guy!: Fans of The Wire will recognize Davide Costabile (Thomas Klebanow), Boris McGiver (Lieutenant Marimow), and Bill Raymond (The Greek) as James Ashley, Alexander Coffroth and Schuyler Colfax, respectively.