Farma Natural Reserve is located among the villages of Monticiano and Roccastrada. The park stretches along the wild and luxuriant valley of the river Farma, which is the most important affluent of the wider river Merse, and the upper course of the river Lanzo, a very long stream flowing into the river Ombrone in Paganico.The portion of the park under competence of Siena is bounded by the left bank of the river Farma, whose course divides the two provinces of Siena and Grosseto.
In the protected area of Grosseto you can find the National Natural Reserve of Belagaio. The Belagaio is located between the river Farma and the river Lenzo. it used to be an ancient feudal castle, but it currently serves as a farm for the Italian State Forestry Department. If you are coming from the route which links up Grosseto and Siena, nearby Petriolo thermal bath, you will be able to gaze at the wildness and harshness of the valley. Val di Farma is characterised by steep hillsides which are entirely covered with a luxuriant vegetation.
The sides create a narrow valley floor with a “V” form, in which you can catch a glimpse of the river flow.
The whole Val di Farma, with a particular focus on the Natural Reserve, presents unequalled naturalistic features for the province of Siena and some of the most relevant characteristics of the entire nation. In fact the park presents a peculiar vegetation and some rare and endemic species that can find a proper wild and uncontaminated shelter.