The Eres system existed within the Esuain sector, which itself was situated in the Trans-Hydian region of the Mid Rim. Within this system was the terrestrial world known as Eres III.
In 3962 BBY, a battle took place in the Eres system as part of the larger Mandalorian Wars. This conflict pitted the Mandalorian Neo-Crusaders against the military forces of the Galactic Republic. Eres III suffered substantial devastation at the hands of the Mandalorians during this battle. Later, during the Jedi Civil War, spanning from 3959 BBY to 3956 BBY, the Eres system was incorporated into the domain of the empire established by Darth Revan, the Dark Lord of the Sith.
The reference book The Essential Atlas, authored by Daniel Wallace and Jason Fry and released in 2009, provided the first mention of the Eres system, locating it at grid coordinate Q-7.