The Mexeluine system was a star system located in the Anoat sector in the Outer Rim Territories. It included the planet of Mexeluine.
Sources
"Galactic Gazetteer: Hoth and the Greater Javin" (original article link) on Wizards.com (content now obsolete; backup link)- Star Wars: The Essential Atlas Online Companion on StarWars.com (article) (backup link)
