Fort-Louis is a commune in the Bas-Rhin department in Grand Est in north-eastern France. It acquired its name and its principal raison d'êt…Fort-Louis is a commune in the Bas-Rhin department in Grand Est in north-eastern France. It acquired its name and its principal raison d'être from a 17th-century fort, known as Fort Louis. More recently the population of the settlement increased between 1962 and 2004 from 137 to 279.