Grand Isle was an Imperial garrison on the planet Vladet, the capital of the Rachuk sector. The base was located inside the crater of an extinct volcano. It was defended by shield generators and two planetary ion cannons, but its old geothermal power tap was insufficient to power the shields and ion cannons simultaneously. The only other defenses on the ground were four TIE/LN starfighters, making Grand Isle heavily reliant on the Rachuk Sector Fleet for protection.
The original role of the base was to discourage piracy in the sector, but it also became the headquarters of Admiral Devlia, the commander of the Rachuk sector Fleet. In 6.5 ABY, Grand Isle was targeted by the New Republic in retaliation against a stormtrooper raid that Devlia had sent against Rogue Squadron's base on Talasea. The Y-wings of Defender Wing broke through the north wall of Grand Isle's crater and destroyed the base with proton torpedoes, killing Admiral Devlia.