The Ahr rises in the middle of the village of
Blankenheim, in the
Eifel region of the German state of
North Rhine-Westphalia, in the basement of a
timber-framed house in an enclosed
spring at a height of . It then flows through the
Schwanenweiher pond below
Blankenheim Castle. The stream, which runs in a south-easterly direction, through the valley meadows of upper Ahr valley, has not cut very deeply into the heights of the Eifel. Much of the upper Ahr valley is protected and follows the
B 258 federal road. Below the hamlet of Ahrdorf in the municipality of Blankenheim, the Ahr reaches its southernmost point and enters the state of Rhineland-Palatine. From
Müsch via
Antweiler to
Fuchshofen, the river runs northwards and turns east at
Schuld heading through
Insul to
Dümpelfeld. Here, the Ahr collects the waters of the Adenauer Bach coming from the right and flowing in a northeasterly direction. In Altenahr, the valley bends to the east and initially follows a very winding course. Here the river is accompanied by the
B 267, although it does not follow every loop in the river. In Altenahr, the largest bend in the river beings; it is protected because of its flora and fauna. From here, the valley becomes a gorge bordered by the steep cliffs of the
Ahr Hills. From Reimerzhoven the valley sides are dominated by vineyards, especially on the south-facing slopes north of the river, particularly around the villages of
Mayschoß,
Rech,
Dernau and
Marienthal. The last narrow point in the Ahr valley occurs below the
Bunte Kuh ("coloured cow"), a rock formation that almost reaches the river and leaves little room for road and railway. In
Walporzheim, the valley widens abruptly, and the Ahr passes through the county town of
Bad Neuenahr. In
Heimersheim, the vineyards end. The valley floor between
Bad Bodendorf on the northern side and
Sinzig on a terrace in the south is dominated by agriculture and fruit and vegetable growing. The mouth of the Ahr lies on the plain of the
Golden Mile, between the
Remagen district of Kripp and the town of Sinzig at a height of about . Since being re-naturalised (from 1979, see aerial photographs) it has been one of the few natural river mouths on the Rhine and is under
protection. Blankenheim Eifel Ahrquelle.jpg|Source of the Ahr (in front of the head) in Blankenheim ahr01.jpg|The middle Ahr below
Altenahr with the rock formation of
Langfig Ahrtal02.jpg|The Ahr by the
Bunte Kuh rock formation at Walporzheim Bundesarchiv Bild 195-0577, Rheinbefliegung, Niederbreisig - Kripp.jpg|The mouth of the Ahr on the Rhine before re-naturalisation (1957) Ahr, Mündung.jpg|The mouth of the Ahr after re-naturalisation. Right: this village of Kripp == Tributaries ==