The Ahr is a river in Germany, a left tributary of the Rhine, which gives its name to the Ahr wine region. Its source is at an elevation of approximately 1,542 feet (470 metres) above sea level in Blankenheim in the Eifel mountain range, in the cellar of a timber-frame house near the castle of Blankenheim. After 11 miles (18 km) it crosses from North Rhine-Westphalia into Rhineland-Palatinate. Length: 55 miles (89 km).