The Northern Military was the remaining faction of the US military located far north, and went to war with Colonel McCullough's Alpha-Omega division for the third act of War for the Planet of the Apes.
Dawn of the Planet of the Apes
Sometime during the Simian Flu pandemic, what remains of the United States military forces relocated to a base somewhere north in North America. In 2026, they made contact with survivors in San Francisco and were attacked by the apes living there. Two days later, they sent Colonel McCullough and a group of soldiers to San Francisco to kill the apes.
War for the Planet of the Apes
As McCullough's forces fought the apes over a year, they've received word that McCullough's son John stopped speaking and went primitive, possibly losing his mind from the war, but it was later revealed the Simian Flu had mutated and is granting the immune humans who survived a fate worse than death: it's robbing them of their speech and higher intellect. The northern military also learned that McCullough has ordered his men to kill all, even their own comrades, who became infected with the mutated virus. They attempted to reason with McCullough and told him they can find a cure for the new viral strain, but McCullough, whom believed the humans hadn't learned from their mistakes when the Simian Flu was created as the potential cure for Alzheimer's, refused and beheaded his superiors.
Ten months later, the north received a message from McCullough, whom threatened them to relieve him of his command by force, forcing the north to deploy the full force of their forces and take down McCullough's militia at an old quarantine facility McCullough and his men took refuge in. One night, before the break of dawn, the northern military reached the facility and opened fire, forcing Alpha-Omega to fire back. By daylight, the north lost all their air support while the ground militia continued on until an explosion destroyed the facility's wall and blew up the facility as well, killing a large number of Alpha-Omega soldiers, minus McCullough whom committed suicide after becoming infected with the mutated Simian Flu, and their Donkey followers. As the ground militia ran forward, they pulled out a couple of Alpha-Omega soldiers who survived the explosion, granting the north victory. As the northern militia cheered, a small handful in the back spotted an injured ape standing on a rock and looking at the mountain range. Before they could open fire, the militia heard a rumble and saw an avalanche, triggered by the explosion, forcing them to run away. Despite their efforts, the entire northern militia and the remains of the Alpha-Omega soldiers were buried alive by the heavy snow and died from hypothermia and suffocation.