D25C is a very challenging mountain road located on the border of Aude department and Ariège department in southwestern France.
The road runs entirely over 1.900m above the sea level. It’s asphalted but very narrow, impassable for 2 cars at the same time. The road creates a shorcut between Col de Pailhères and Col des Trabesses.
The road is not plowed in winters. There’s a high risk of rock slides. The drive is pretty steep. It’s 550m long with an elevation gain of 72 meters. The average gradient is 13.09%.