The El-Aurian system was a planetary star system located several thousand light years from Federation space. The system contained at least one populated planet, the El-Aurian homeworld.
During the late 23rd century the system was invaded and a majority of its population was wiped out by the Borg. Those El-Aurians who managed to survive the invasion were scattered throughout the galaxy. (TNG: "Q Who"; Star Trek Generations)
Guinan, a bartender aboard the USS Enterprise-D, was from the El-Aurian system. (citation needed • edit) Odo identified Martus Mazur as a refugee from the El-Aurian system during Mazur's visit to Deep Space 9 in 2370. (DS9: "Rivals")