Factual error: The pub sign states "whisky" - Irish whiskey is always spelled with an E.
Factual error: ***SPOILER ALERT*** When Padraic sets Colm's house on fire, he ignites the fires using a Zippo lighter, which would not be produced until 1933, ten years after the film is set.
Factual error: April 1st, 1923 was a Sunday, not a Friday as shown on Padraic's calendar in the film.
Continuity mistake: In the bar scene after Padraic tries the "new tactic" on Colm, in some shots of the scene you can see 4 pint glasses on the table (three empty and one full for Colm), and in other shots there are 5 (three empty, one full and one half full). (01:20:47)