Kelok 9, Mountain road in Lima Puluh Kota Regency, Indonesia

Kelok 9 is a 300-metre winding road with nine sharp turns, about 5 metres wide, climbing roughly 80 metres through the Bukit Barisan between the Air Putih and Harau nature reserves. A 2,537-metre overpass, opened in 2013, runs above it on concrete pillars up to 58 metres high, crossing the hillsides six times.

The original route was built between 1908 and 1914 by the Dutch East Indies government. The modern overpass that exists today was opened in 2013, replacing the older alignment.

The name Kelok Sembilan means "nine sharp turns" in Minangkabau, the language of the surrounding Harau area. The old road, only 5 metres wide, was long the main link between West Sumatra and Riau; in 2000 it carried 9,000 to 11,000 vehicles a day, half of them loaded with agricultural and livestock produce. The flyover was opened early for the Lebaran homecoming rush and for the Tour de Singkarak cycling race.

The route is open daily and requires attentiveness due to the many turns, which can be demanding for inexperienced drivers. It is advisable to travel during daylight hours and adjust speed to the tightest sections.

Kelok means bend in Minangkabau, the local language, not Sundanese; the name Kelok Sembilan refers to the nine sharp turns of the old 300-metre road. The 2.5 km flyover built over it has six bridges, and its fourth span is a 462-metre concrete arch on bore piles sunk 20 metres deep to resist earthquakes.