Originally, part 3 was intended to be a prequel, telling the story of the very first Purge. This idea was scrapped when Frank Grillo accepted James DeMonaco's offer to reprise the character of Sergeant Leo Barnes.
The Purge franchise has expanded its universe more throughout each film. The first film takes place in a house. The second film takes place in the streets. The third film takes place in the government. Also, each film looks at the Purge through different points of view. The first film is told from the rich. The second is told from the poor. The third is told from the political side
Plot Hole: In the beginning of the movie, we see Senator Roan and her family during the purge 18 years before the events of the movie. However, in the previous movie, Purge:Anarchy, the purge is announced as "the 6th Annual Purge". Since this movie is set only 2 years after Purge: Anarchy, there is no way Senator Roan's family was killed in a purge 18 years ago because purging didn't exist.
Raymond J. Barry and Elizabeth Mitchell (Senator Roan) played characters on the show Lost (2004). There is a subtle nod to Lost (2004), with the appearance of the Apollo candy bar, the candy bar the Kimmy tries to steal from Joe's store, in the beginning of this movie.
In Spain, all the films of the trilogy have different titles, but the same subtitle to identify it: The Purge: La Noche de las bestias (The Purge: Night of the Beasts) (2013), Anarchy: La Noche de las bestias (Anarchy: Night of the Beasts) (2014), and Election: La Noche de las bestias (Election: Night of the Beasts) (2016).
Frank Grillo plays a character named Sergeant Barnes. In the Marvel Cinematic Universe Frank Grillo plays the villain Crossbones who is the enemy of Sergeant James "Bucky" Barnes/The Winter Soldier played by Sebastian Stan.
Actress Carmen Ejogo, who played Eva Sanchez in The Purge: Anarchy (2014), was interviewed by Collider if she would reprise the role in The Purge: Election Year (2016). She told them, "No. (laughs) I believe as an actress, you get to change," stating that she would not return.
At the end it is revealed that the senator wins and tries to end the Purge but the news reporter says that there are fans of the NFFA making violent protests. This is a possible reference to a fourth Purge movie.