Map - Karlsruhe (Stadtkreis Karlsruhe)

Karlsruhe ( ; South Franconian: Kallsruh) is the third-largest city of the German state (Land) of Baden-Württemberg after its capital of Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. It is also a former capital of Baden, a historic region named after Hohenbaden Castle in the city of Baden-Baden. Located on the right bank of the Rhine near the French border, between the Mannheim/Ludwigshafen conurbation to the north and Strasbourg/Kehl to the south, Karlsruhe is Germany's legal center, being home to the Federal Constitutional Court (Bundesverfassungsgericht), the Federal Court of Justice (Bundesgerichtshof) and the Public Prosecutor General of the Federal Court of Justice (Generalbundesanwalt beim Bundesgerichtshof).

Karlsruhe was the capital of the Margraviate of Baden-Durlach (Durlach: 1565–1718; Karlsruhe: 1718–1771), the Margraviate of Baden (1771–1803), the Electorate of Baden (1803–1806), the Grand Duchy of Baden (1806–1918), and the Republic of Baden (1918–1945). Its most remarkable building is Karlsruhe Palace, which was built in 1715. There are nine institutions of higher education in the city, most notably the Karlsruhe Institute of Technology (Karlsruher Institut für Technologie). Karlsruhe/Baden-Baden Airport (Flughafen Karlsruhe/Baden-Baden) is the second-busiest airport of Baden-Württemberg after Stuttgart Airport, and the 17th-busiest airport of Germany.

Karlsruhe lies completely to the east of the Rhine, and almost completely on the Upper Rhine Plain. It contains the Turmberg in the east, and also lies on the borders of the Kraichgau leading to the Northern Black Forest.

The Rhine, one of the world's most important shipping routes, forms the western limits of the city, beyond which lie the towns of Maximiliansau and Wörth am Rhein in the German state of Rhineland-Palatinate. The city centre is about 7.5 km from the river, as measured from the Marktplatz (Market Square). Two tributaries of the Rhine, the Alb and the Pfinz, flow through the city from the Kraichgau to eventually join the Rhine.

The city lies at an altitude between 100 and 322 m (near the communications tower in the suburb of Grünwettersbach). Its geographical coordinates are 49°N, 8.4°W; the 49th parallel runs through the city centre, which puts it at the same latitude as much of the Canada–United States border, the cities Vancouver (Canada), Paris (France), Regensburg (Germany), and Hulunbuir (China). Its course is marked by a stone and painted line in the Stadtgarten (municipal park). The total area of the city is 173.46 km2, hence it is the 30th largest city in Germany measured by land area. The longest north–south distance is 16.8 km and 19.3 km in the east–west direction.

Karlsruhe is part of the urban area of Karlsruhe/Pforzheim, to which certain other towns in the district of Karlsruhe, such as Bruchsal, Ettlingen, Stutensee, and Rheinstetten, as well as the city of Pforzheim, belong.

The city was planned with the palace tower (Schloss) at the center and 32 streets radiating out from it like the spokes of a wheel, or the ribs of a folding fan, so that one nickname for Karlsruhe in German is the "fan city" (Fächerstadt). Almost all of these streets survive to this day. Because of this city layout, in metric geometry, Karlsruhe metric refers to a measure of distance that assumes travel is only possible along radial streets and along circular avenues around the centre.

The city centre is the oldest part of town and lies south of the palace in the quadrant defined by nine of the radial streets. The central part of the palace runs east–west, with two wings, each at a 45° angle, directed southeast and southwest (i.e., parallel with the streets marking the boundaries of the quadrant defining the city center).

The market square lies on the street running south from the palace to Ettlingen. The market square has the town hall (Rathaus) to the west, the main Lutheran church (Evangelische Stadtkirche) to the east, and the tomb of Margrave Charles III William in a pyramid in the buildings, resulting in Karlsruhe being one of only three large cities in Germany where buildings are laid out in the neoclassical style.

The area north of the palace is a park and forest. Originally the area to the east of the palace consisted of gardens and forests, some of which remain, but the Karlsruhe Institute of Technology (founded in 1825), Wildparkstadion football stadium, and residential areas have been built there. The area west of the palace is now mostly residential.