Koenigswinter is a town and summer resort in the Rhein-Sieg district, in North Rhine-Westphalia, Germany.
It is situated on the right bank of the Rhine, opposite to Bonn, at the foot of the Siebengebirge.
The romantic Drachenfels, crowned by the ruins of a castle built in the early 12th century by the archbishop of Cologne, rises behind the town. From the summit, which can be accessed by the Drachenfels Railway, there is a magnificent view, celebrated by Lord Byron in Childe Harold's Pilgrimage. A cave in the hill is said to have sheltered the dragon which was slain by the hero Siegfried. The mountain is quarried, and from 1267 onward supplied stone (trachyte) for the building of Cologne Cathedral.
The castle of Drachenburg, built in 1883, is on the north side of the hill.
Koenigswinter has a Roman Catholic (St. Remigius) and an Evangelical church, some small manufactures and a little shipping. It has a monument to the poet Wolfgang Müller.
Near the town are the ruins of the Abbey of Heisterbach.