Bas-Rhin is a department in Alsace which is a part of the Grand Est super-region of France. The name means 'Lower Rhine', referring to its lower altitude among both French Rhine departments: it is downstream of the Haut Rhin (Upper Rhine) department. Note that both belong to the European Upper Rhine region. It is, with the Haut Rhin (Upper Rhine), one of the two departments of the traditional Alsace region. The more populous and densely populated of the pair, it had 1,125,559 inhabitants in 2017. The prefecture is based in Strasbourg. The INSEE and Post Code is 67.