The Cervo Valley extends for approximately 16 kilometers along the Cervo River, from which it takes its name. It occupies the mountainous area of the Biella province bordering the Aosta Valley, covering an area of approximately 73 km². The valley borders the Gressoney Valley in the Aosta Valley, the Valsesia to the northwest, and the Sessera Valley to the southeast. Its most important center is Andorno, located midway down the valley, which is why its various names include the Andorno Valley, Sarvo, Valsaar, and Valdandorn.
Its territory is divided into an upper and lower valley, where the first is narrow and sparsely populated, rich in beech and chestnut forests, mountain pastures and high-altitude wasteland, and known for several small villages overlooking the stream, including Rosazza, Piedicavallo, and Campiglia Cervo. Here we find the highest mountains in the wool-producing province: Mount Cresto (2,545 m), Punta Tre Vescovi (2,501 m), and the summit of Bo (2,556 m).
The Lower Valley, more open and more populated, is also rich in woods and is home to most of the area's inhabited centers, including Miagliano, which, at 0.66 km2, is the smallest Italian municipality in terms of territorial extension.
The first recorded settlements date back to Roman times, and its inhabitants have Mediterranean and Celtic origins. After centuries of pastoralism, the valley dwellers began to exploit the land to quarry syenite, becoming highly skilled and highly regarded stonemasons. These socialized workers were involved in the construction of impressive works such as those in the towns of Fenestrelle and Exilles , and in Bard . With the Industrial Revolution, the Cervo Valley also became involved in the production of textiles, for which the province of Biella is still famous today, with the appearance of several factories along the Cervo stream. In addition to providing the energy needed to power the machinery, the stream's fresh water, low in minerals and calcium, is particularly suitable for washing wool.
