The Gander (also called Altbach in France) is a river which flows in Luxembourg and in the French département Moselle, tributary of the Moselle River (left side). Its source is in the commune of Frisange, southern Luxembourg. It flows generally southeast, and from Altwies until Emerange (commune of Burmerange) it forms the French-Luxembourgish border. From Emerange until its outflow into the Moselle at Haute-Kontz, it flows through France. The largest town on the Gander is Mondorf-les-Bains.