River, southwestern Germany. It rises in the
Black Forest near the headwaters of the
Danube River and is 228 mi (367 km) long. It flows north and northeast, passing
Stuttgart. Its picturesque valley becomes broader and deeper, passing hills crowned by feudal castles. It flows past
Heidelberg and enters the
Rhine River at
Mannheim.
For more information on Neckar River, visit Britannica.com.