Upper Rhine Plain in the context of "Rastatt"

The international border between the modern states of France and Germany has a length of 450 km (280 mi). The southern portion of the border, between Saint-Louis at the border with Switzerland and Lauterbourg, follows the River Rhine (Upper Rhine) in a south-to-north direction through the Upper Rhine Plain. The border then turns westward until it reaches the tripoint between France, Germany and Luxembourg.

Mainz (German: [maɪnts] ; see below) is the capital and largest city of the German state of Rhineland-Palatinate, and with around 223,000 inhabitants, it is Germany's 35th-largest city. It lies in the Rhine-Main Metropolitan Region—Germany's second-largest metropolitan region after Rhine-Ruhr—which also encompasses the cities of Frankfurt am Main, Wiesbaden, Darmstadt, Offenbach am Main, and Hanau.

Mainz is located at the northern end of the Upper Rhine Plain, on the left bank of the Rhine. It is the largest city of Rhenish Hesse, a region of Rhineland-Palatinate that was historically part of Hesse, and is one of Germany's most important wine regions because of its mild climate. Mainz is connected to Frankfurt am Main by the Rhine-Main S-Bahn rapid transit system. Before 1945, Mainz had six boroughs on the other side of the Rhine (see: de:Rechtsrheinische Stadtteile von Mainz). Three have been incorporated into Wiesbaden (see: de:AKK-Konflikt), and three are now independent.

Upper Rhine (German: Oberrhein [ˈoːbɐˌʁaɪn] ; French: Rhin Supérieur is the section of the Rhine between the Middle Bridge in Basel, Switzerland, and the Rhine knee in Bingen, Germany. Representing kilometres 167 to 529 of the river it is surrounded by the Upper Rhine Plain (Oberrheinische Tiefebene). Most of its upper section marks the France–Germany border.

The Upper Rhine is one of four sections of the river between Lake Constance and the North Sea, and is succeeded downstream by the Middle Rhine and Lower Rhine; only the High Rhine and Alpine Rhine lie above it. The countries and states along the Upper Rhine are Switzerland, France (Alsace) and the German states of Baden-Württemberg, Rhineland-Palatinate and Hesse. The largest cities along the river are Basel, Mulhouse, Strasbourg, Karlsruhe, Mannheim, Ludwigshafen and Mainz.

The Kraichgau (German: [ˈkʁaɪçɡaʊ] ) is a hilly region in Baden-Württemberg, southwestern Germany. It is bordered by the Odenwald and the Neckar to the North, the Black Forest to the South, and the Upper Rhine Plain to the West. To the east, its boundary is considered to be the Stromberg and the Heuchelberg.

The largest towns of the Kraichgau are Sinsheim, Eppingen, and Bretten. On the western end of the Kraichgau is the town of Bruchsal, the gateway to the Rhineland plains.

Heidelberg (/ˈhaɪdəlbɜːrɡ/; German: [ˈhaɪdl̩bɛʁk] ; Palatine German: Heidlberg) is the fifth-largest city in the German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of students, it is Germany's 51st-largest city. Located about 78 km (48 mi) south of Frankfurt, Heidelberg is part of the densely populated Rhine-Neckar Metropolitan Region which has its centre in Mannheim.

Heidelberg is located on the Neckar River, at the point where it leaves its narrow valley between the Oden Forest and the Little Oden Forest, and enters the wide Upper Rhine Plain. The old town lies in the valley, the end of which is flanked by the Königstuhl in the south and the Heiligenberg in the north. The majority of the population lives in the districts west of the mountains in the Upper Rhine Plain, into which the city has expanded over time.

Mannheim (German pronunciation: [ˈmanhaɪm] ; Palatine German: Mannem or Monnem), officially the University City of Mannheim (German: Universitätsstadt Mannheim), is the second-largest city in Baden-Württemberg after Stuttgart, the state capital, and Germany's 21st-largest city, with a population of over 315,000. It is located at the border with Rhineland-Palatinate. The city is the cultural and economic centre of the Rhine-Neckar, Germany's seventh-largest metropolitan region, with nearly 2.4 million inhabitants.

Mannheim is located at the confluence of the Upper Rhine and the Neckar in the Kurpfalz (Electoral Palatinate) region of northwestern Baden-Württemberg. The city lies in the Upper Rhine Plain, Germany's warmest region, between the Palatine Forest and the Oden Forest. Mannheim forms a continuous urban zone of around 500,000 inhabitants with Ludwigshafen am Rhein in the Rhineland-Palatinate, while some northern suburbs lie in Hesse; Hamburg is the only other German city with a presence in two states other than its own.

Freiburg im Breisgau or simply Freiburg is the fourth-largest city of the German state of Baden-Württemberg after Stuttgart, Mannheim and Karlsruhe. Its built-up area has a population of about 355,000 (2021), while the greater Freiburg metropolitan area ("Einzugsgebiet") has about 660,000 (2018).

Freiburg is located at the southwestern foothills of the Black Forest, on the Dreisam River, a tributary of the Elz. It is Germany's southwestern- and southernmost city with a population exceeding 100,000. It lies in the Breisgau, one of Germany's warmest regions, in the south of the Upper Rhine Plain. Its city limits reach from the Schauinsland summit (1,284 metres (4,213 ft)) in the Black Forest to 3 kilometres (1.9 mi) east of the French border, while Switzerland is 42 kilometres (26 mi) to the south. The city is situated in the major wine-growing region of Baden and, together with Offenburg, serves as a tourist entry-point to the scenic Black Forest. According to meteorological statistics, Freiburg held the all-time German temperature record of 40.2 °C (104.4 °F) from 2003 to 2015.