Koppenberg, Mountain pass in Oudenaarde, Belgium.

Koppenberg is a 79 m hill near Melden in Oudenaarde, made up of two parts: the western Rotelenberg (78 m) and the eastern Koppenberg (79 m). The climb runs from the west via the Steengat, a cobbled road protected as a monument since 1995, with a maximum gradient of 22 percent, or 25 percent on the inside bend. A banner reading "KOPPENBERG vakantie woning" hangs beside the narrow paved lane.

The Koppenberg was first included in the Tour of Flanders in 1976 and featured annually until 1987. That year Danish rider Jesper Skibby, leading alone, slowed on the climb; the commissaire's car following him knocked him down and ran over his rear wheel, ending his race. The climb was then left out for 15 years and returned in 2002 after the road was widened and repaved. It was dropped again in 2007 over the unsafe surface, restored that September, and has featured every year since 2008; the women's race added it in 2022.

The name Koppenberg derives from "kinderkoppen", Dutch slang for the rounded cobblestones that resemble children's heads. The same stones give the climb its nickname, "de bult van Melden", after the nearby village. Since 1976 the hill has been a fixture of Flemish cycling culture, and the annual Koppenbergcross cyclo-cross is held here on All Saints' Day.

The cobbled climb is short but reaches 22 percent on its steepest bend, so walkers should wear shoes with grip and take the ascent slowly. The road is narrow and used by cyclists and race vehicles; step aside rather than block the lane. The wooded sections on top, including the 29-hectare Koppenbergbos, are open to walkers.

The surrounding forest holds oak trees aged between 150 and 200 years, creating a natural setting that contrasts with the stark road surface. Each spring wild hyacinths bloom in masses across the area, transforming the landscape with their blue flowers.