Karlsruhe (/ˈkɑːrlzruːə/ KARLZ-roo-ə, US also /ˈkɑːrls-/ KARLSS-, German: [ˈkaʁlsˌʁuːə]), formerly spelled Carlsruhe in English, is the third-largest city of the German federal state of Baden-Württemberg after its capital of Stuttgart, and Mannheim. Its 308,436 inhabitants make it the 21st-largest city of Germany. On the right bank of the Rhine, the city lies near the French-German border, between the Mannheim/Ludwigshafen conurbation to the north, and the Strasbourg/Kehl conurbation to the south. It is the largest city of Baden, a historic region named after Hohenbaden Castle in the city of Baden-Baden. Karlsruhe is also the largest city in the South Franconian dialect area (transitional dialects between Central and Upper German), the only other larger city in that area being Heilbronn