The Département du Bas-Rhin (67) is in northern Alsace in eastern France, bordering on Germany, both north and east.
In 1790 the department was formed from Alsace, a region which had come largely under French control in the 17th century, though some German princes kept proprietorial rights until the Revolution. Alsace was traditionally divided between Upper and Lower Alsace: the Department of the Bas-Rhin joined the latter with a district around Petite-Pierre (which juts westwards in the north of the department), which had previously belonged to the Dukes of Zweibrücken and been regarded as part of Lorraine.
From 1871 to 1918 the Bas-Rhin was the district of Unter-Elsass in the Reichsland of Elsass-Lothringen in the German Empire. It was also absorbed by the Third Reich in 1940, but was liberated in the winter of 1944-5.
It now belongs to the region of Alsace.
Its capital is Strasbourg. The sub-prefectures of the other arrondissements are been Saverne, Wissembourg, Sélestat, Erstein, Haguenau and Molsheim. The first three were sub-prefectures before 1870, Sélestat having replaced Barr in 1806. The Bishopric has been Strasbourg, an ancient see, which has included the Haut-Rhin as well since 1802.