July 2, 1921 is a date featured in the episode "Battle of the Century". Events of the day include:
- World Heavyweight Boxing Champion Jack Dempsey successfully defends his title against challenger Georges Carpentier. The fight was billed as the "battle of the century".
- Emily Schroeder is formally diagnosed with polio.
- Manny Horvitz survives an assination attempt and kills his attacker Alfred Gordetsky
- John McGarrigle is murdered by fellow Irish Republican Army (IRA) member Patrick allowing IRA leader Bill Neilan to trade liquor for guns with Nucky Thompson.
- A trial date (August 23 1921) is set for Nucky's election rigging case.
- Nucky departs Ireland to return to America.