The Hosnian system, a star system nestled within the galaxy's Core, encompassed several planets: Cardota, Courtsilius, Hosnian, Hosnian Prime, and Raysho.
During the Battle of Endor, an Imperial armada launched a surprise attack on the Hosnian System, targeting the Core Worlds. The armada encountered resistance from the MC75 Star Cruisers Temperance and Accordance. While the Accordance was lost, the Temperance rescued the survivors and ultimately secured victory.
Approximately a month following the Battle of Jakku, a female news anchor from the Hosnian system broadcasted news of an impending Imperial surrender. However, she noted that the New Republic Defense Fleet would maintain a state of war readiness for the foreseeable future. This transmission was intercepted by Imperial remnant forces as distant as the Queluhan Nebula.
In 28 ABY, the New Republic Senate was located within this system, specifically on Hosnian Prime.
Hosnian Prime, along with all other orbiting planetary bodies around the system's sun, were completely destroyed in 34 ABY when the First Order's Starkiller Base superweapon discharged a phantom energy beam. The nature of phantom energy made the system's destruction visible across the galaxy through a tear in sub-hyperspace. This event was witnessed by individuals at Maz Kanata's castle on Takodana, as well as those on Vardos. The beam caused Hosnian Prime's core to ignite in a pocket nova, briefly transforming the system into a binary one.