Obernai is commune in the Bas-Rhin department in Alsace in north-eastern France. It lies on the eastern slopes of the Vosges mountain…Obernai is commune in the Bas-Rhin department in Alsace in north-eastern France. It lies on the eastern slopes of the Vosges mountains. Obernai is a rapidly growing city, its number of inhabitants having gone up from 6,304 in 1968 to 11,279 in 2017.