Bas-Rhin in the context of Hôtel de Ville, Benfeld

The Rhine (/raɪn/ RYNE) is one of the major rivers of Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Swiss-Austrian border. From Lake Constance downstream, it forms part of the Swiss-German border. After that the Rhine defines much of the Franco-German border. It then flows in a mostly northerly direction through the German Rhineland. Finally, the Rhine turns to flow predominantly west to enter the Netherlands, eventually emptying into the North Sea. It drains an area of 185,000 km.

Its name derives from the Gaulish Rēnos. There are two German states named after the river, North Rhine-Westphalia and Rhineland-Palatinate, in addition to several districts (e.g. Rhein-Sieg). The departments of Bas-Rhin and Haut-Rhin in Alsace (France) are also named after the river. Some adjacent towns are named after it, such as Rheinau, Stein am Rhein, Rheineck, Rheinfelden (Switzerland) and Rheinfelden (Germany).

Strasbourg (UK: /ˈstræzbɜːrɡ/ STRAZ-burg, US: /ˈstrɑːsbʊərɡ, ˈstrɑːz-, -bɜːrɡ/ STRAHSS-boorg, STRAHZ-, -⁠burg; French: [stʁasbuʁ] ; German: Straßburg [ˈʃtʁaːsbʊʁk] ) is the prefecture and largest city of the Grand Est region of eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin department and the official seat of the European Parliament.

The city has about three hundred thousand inhabitants, and together Greater Strasbourg and the arrondissement of Strasbourg have over five hundred thousand. Strasbourg's metropolitan area had a population of 860,744 in 2020, making it the eighth-largest metro area in France and home to 14% of the Grand Est region's inhabitants. The transnational Eurodistrict Strasbourg-Ortenau had a population of roughly 1,000,000 in 2022. Strasbourg is one of the de facto four main capitals of the European Union (alongside Brussels, Luxembourg and Frankfurt), as it is the seat of several European institutions, such as the European Parliament, the Eurocorps and the European Ombudsman of the European Union. An organization separate from the European Union, the Council of Europe (with its European Court of Human Rights, its European Directorate for the Quality of Medicines most commonly known in French as "Pharmacopée Européenne", and its European Audiovisual Observatory) is also located in the city.

Haut-Rhin (French pronunciation: [oʁɛ̃] ) is a department in the Grand Est region, France, bordering both Germany and Switzerland. It is named after the river Rhine. Its name means Upper Rhine. Haut-Rhin is the smaller and less populated of the two departments of the former administrative Alsace region, the other being Bas-Rhin (Lower Rhine), especially after the 1871 cession of the southern territory known since 1922 as the Territoire de Belfort, although it is still rather densely populated compared to the rest of metropolitan France. It had a population of 767,083 in 2021.

On 1 January 2021, the départemental collectivities of Bas-Rhin and Haut-Rhin were merged into the European Collectivity of Alsace.

Alsace is a cultural region and a territorial collectivity in the Grand Est administrative region of northeastern France, on the west bank of the upper Rhine, next to Germany and Switzerland. In January 2021, it had a population of 1,919,745. Alsatian culture is characterized by a blend of German and French influences.

Until 1871, Alsace included the area now known as the Territoire de Belfort, which formed its southernmost part. From 1982 to 2016, Alsace was the smallest administrative région in metropolitan France, consisting of the Bas-Rhin and Haut-Rhin departments. Territorial reform passed by the French Parliament in 2014 resulted in the merger of the Alsace administrative region with Champagne-Ardenne and Lorraine to form Grand Est. On 1 January 2021, the departments of Bas-Rhin and Haut-Rhin merged into the new European Collectivity of Alsace but remained part of the region Grand Est.

The Fort de Mutzig, also known as Feste Kaiser Wilhelm II, is located near the town of Mutzig, in the Bas-Rhin department of France. It is one of the fortifications built by Germany at the end of the 19th century to defend Strasbourg.

It was the first new fortification built in what was then German territory after the invention of high explosives, which rendered earlier masonry fortifications obsolete.

The European Collectivity of Alsace (French: Collectivité européenne d'Alsace, pronounced [kɔlɛktivite øʁɔpeɛn dalzas], abbr. CEA) is a territorial collectivity in the Alsace region of France. On 1 January 2021, the territorial collectivities of the Bas-Rhin and Haut-Rhin departments merged to form a new territorial collectivity, but remained part of the Grand Est region. The creation of this new entity was approved by the French Parliament on 25 July 2019 and Law 2019-816, which delimits its powers, was promulgated on 2 August 2019.

Alsatian voters had already voted in favour of the creation of a single territorial collectivity in a referendum in 2013; however, in the less populous of the two departments, Haut-Rhin, a majority of voters had rejected the proposal.

Meurthe-et-Moselle (French pronunciation: [mœʁt e mɔzɛl] , lit. 'Meurthe and Moselle') is a department in the Grand Est region of France, named after the rivers Meurthe and Moselle. Its prefecture and largest city is Nancy and it borders the departments of Meuse to the west, Vosges to the south, Moselle and Bas-Rhin and it borders the Belgian province of Luxembourg and the country of Luxembourg by the canton of Esch-sur-Alzette to the north. It had a population of 733,760 in 2019.

Eurométropole de Strasbourg (French pronunciation: [øʁɔmetʁɔpɔl də stʁasbuʁ]) is the métropole, an intercommunal structure, centred on the city of Strasbourg. It is located in the Bas-Rhin department, in the Grand Est region, northeastern France. It was created in January 2015, replacing the previous Communauté urbaine de Strasbourg, and covers that part of the Strasbourg metropolitan area that lies in France. Its area is 337.6 km. Its population was 514,651 in 2021, of which 291,313 is in Strasbourg proper. The annual budget of the métropole was €1.897 billion in 2020.

The arrondissement of Strasbourg (French: Arrondissement de Strasbourg; Alsatian: Arrondissement Strossburi) is an arrondissement of France in the Bas-Rhin department in the Grand Est region. It has 33 communes. Its population is 514,651 (2021), and its area is 337.6 km (130.3 sq mi).

Lauterbourg (French pronunciation: [lotɛʁbuʁ] or [lautəʁbuʁ]; German: Lauterburg) (historically in English: Lauterburgh) is a commune and Bas-Rhin department in the Grand Est administrative region in north-eastern France. Situated on the German border and not far from the German city of Karlsruhe, it is the easternmost commune in Metropolitan France (excluding the island of Corsica). The German town across the border is Neulauterburg.

Mutzig (French pronunciation: [mytsik] or [mutsik]; German: Mützig) is a commune in the Bas-Rhin department in Grand Est, in north-eastern France. The commune of Mutzig is located at the entrance of the Bruche river valley, on the Route des Vins d'Alsace.

Ortenaukreis (Low Alemannic: Ortenaukrais; French: Arrondissement de l'Ortenau) is a Landkreis (district) in the west of Baden-Württemberg, Germany. Neighboring districts are (clockwise from north) Rastatt, Freudenstadt, Rottweil, Schwarzwald-Baar and Emmendingen. To the west it borders the French Bas-Rhin département.

Emmendingen (German: Landkreis Emmendingen) is a Landkreis (district) in the west of Baden-Württemberg, Germany. Neighbouring districts are (from north clockwise) Ortenaukreis, Schwarzwald-Baar, Breisgau-Hochschwarzwald and the district-free city Freiburg. To the west it borders the French département Bas-Rhin.

Rhenish Franconian or Rhine Franconian (German: Rheinfränkisch [ˈʁaɪnfʁɛnkɪʃ] ) is a dialect chain of West Central German. It comprises the varieties of German spoken across the western regions of the states of Saarland, Rhineland-Palatinate, northwest Baden-Württemberg, and Hesse in Germany. It is also spoken in northeast France, in the eastern part of the département of Moselle in the Lorraine region, and in the north-west part of Bas-Rhin in Alsace. To the north, it is bounded by the Sankt Goar line (or das–dat line) which separates it from Moselle Franconian; to the south, it is bounded by the Main line which is also referred to as the Speyer line which separates it from the Upper German dialects.

The Alsace single territorial collectivity referendum (French: référendum sur la Collectivité territoriale d'Alsace) was a referendum held on Sunday, 7 April 2013 in Alsace, France, which aimed at the creation of the single territorial collectivity of Alsace through the merging of the regional council of Alsace and the departmental councils of Bas-Rhin and Haut-Rhin. Even though there was a 57.65% majority of "Yes" votes, the project was not approved, as two other requirements (a majority in favour in both departments and a voter quorum) were not met.

Wissembourg (French pronunciation: [visɑ̃buʁ] ; South Franconian: Weisseburch [ˈvaɪsəbʊʁç]; German: Weißenburg [ˈvaɪsn̩bʊʁk] ) is a commune in the Bas-Rhin department in Grand Est in northeastern France.

Wissembourg was a sub-prefecture of the department until 2015. The name Wissembourg is a Gallicized version of Weißenburg (Weissenburg) in German meaning "white castle". The Latin place-name, sometimes used in ecclesiastical sources, is Sebusium.