February 13, 1921 is a date featured in the Season 2 episode "21". Events of the day include:
- Rose Van Alden returns to the family home in White Plains, New York, unaware that her husband Nelson is living in a boarding house with Lucy Danziger, who is pregnant with his child.
- Jimmy Darmody and Richard Harrow steal the booze stored in Chalky White's abandoned warehouse and sell it to Mickey Doyle.
- Nucky Thompson is arrested by Solomon Bishop, Deputy US Attorney for the State of New Jersey and the New Jersey State Police for voting fraud in the 1920 Atlantic City Local Election.