Vallée du Fango, Biosphere reserve in Haute-Corse, France.

Vallée du Fango is a protected natural area in Corsica's mountains with rivers, waterfalls, and different elevation zones from valleys to peaks. The region contains forests, shrubland, and a range of animal and plant species living in different habitats.

The area was recognized as a UNESCO Biosphere Reserve in 1977 to protect its ecological diversity. This designation established its importance for scientific research and nature conservation across Europe.

The valley corresponds to the historic piève of Filosorma and takes in parts of Galéria, Manso and Calenzana. The name Fango is sometimes spelled Fangu. The Piriu holm-oak stand has not been worked since 1850, and the river holds the "Site rivière sauvage" label from Corsica's environment office.

The region offers hiking trails of different difficulty levels, supported by informational signs and plaques about the environment. Visitors should bring proper footwear and plenty of water, as the trails are hilly and sometimes steep.

The Fango's water is very low in dissolved minerals because three quarters of its dissolved elements come from the atmosphere, and its bed of rhyolite rock keeps the water clear. The Piriu holm oak stand, 77.9 ha, has not been exploited since 1850, and some of its evergreen oaks are counted among the oldest in the world.