Mannheim, Germany, satellite image. Mannheim is situated in the state of Baden-Wuttemburg. The city has a population of around 320,000 inhabitants and is situated on the delta of the River Rhine which flows northwards from bottom centre and the River Neckar which runs westwards from the upper centre. The city also has the second largest river port in Germany. Mannheim is the only German city which has a central area that is built on a grid pattern. Its main railway station is an important train junction and part of the ICE (Intercity Express) high speed train system.