Now that it has been officially announced that Mockingjay will be split into two movies NextMovie speculates where that division will happen.

Peeta, the Messenger

There's a moment in "Mockingjay" when the Capitol presents their new prisoner Peeta Mellark to plea for the rebels to discontinue their dangerous revolutions. They've been holed up in District 13 and filming anti-Capitol propaganda videos in the districts, and they've already experienced the fallout from one ill-fated trip to District 8.
When Peeta's first appearance on Capitol TV doesn't work, the government tries again, this time with a Peeta shown to be savagely beaten. Peeta — obviously scripted — nixes the diplomacy and addresses Katniss directly in the interview. Katniss rightly interprets this as a direct warning to District 13 that an attack is imminent. The group dives lower into the holding and the attack indeed begins. The sound of those bombs dropping upon the rebels' stronghold sure would leave us trembling and ravenous for resolve.

Deadly Rescue Mission

Katniss takes a hit on one of her propos missions for District 13, and when she wakes up in the hospital, she gets some troubling news: Gale and others have been sent on a rescue mission to retrieve Peeta and Finnick Odair's love Annie. It's a dangerous ordeal. Katniss faces the reality that she may lose not one but both of the boys she cares about, and there's nothing she can do to stop it ... Scary, scary!

Peeta Returns ... Sort Of

There's another split potential moment when Gale and team do return successfully from their rescue mission. They've saved Peeta and some of the others from the Capitol, and she's relieved about that. When she goes to see him and he rushes over to her, though, and rather than the warm loving embrace she was expecting, he lunges for her throat.
This is not the same Peeta she's always known. All bets are off now. Splitting the two films at this point would give the filmmakers an opportunity to really play up Peeta's dramatic rescue and the consequences of Katniss' acceptance of the role of the Mockingjay. Not only would this be a frightening and intense moment to end with, but it would also set the stage well for the later events to come between them and for the revolution at large.

Katniss Takes a Bullet

Lionsgate
Once Katniss discovers that Peeta is no longer the boy who's loved her for always, she also begins to discover a cruel side to Gale. He's got some strange opinions about some potentially inhumane weapons developed by District 13. Sure, they've shared a couple of kisses by then, but when he suggests trapping the citizens of District 2's stronghold, the comparisons between those people and her father are inevitable. Both of the boys she loves are now forever changed human beings.
As she begins to reluctantly create another of her anti-Capitol vids celebrating their horrific win, some of District 2's pitiful survivors begin to emerge. Katniss steps up to rescue one of them from her own people, and someone points a gun on her. She offers up her own life. It's what the Capitol wants, she contends. She then tries to rally everyone together to fight as one against the Capitol, and that's when a bullet hits her. For obvious reasons, this would definitely leave "Hunger Games" fans clammoring for "Part 2."

A Wayward Peeta Joins the Team

After Katniss recovers from the District 2 incident, and once Peeta begins to show his own signs of improvement, she decides not to give up on the fight. She plays along with the tactics of District 13 to stay safe, but she's got her own agenda in mind. She's got her sights set on the Capitol but agrees to join as the rebels head through District 12 to start. Goings are slow at first, but one of her team members does die thanks to a pod attack.
When a replacement soldier shows up, it's Peeta, who's nowhere near 100 percent Team Katniss. Katniss realizes that Alma Coin, the leader of District 13, wants her dead. Peeta admits that Katniss is now more dangerous to the mission alive than dead. Dun dun dun!