The town of Pelago is at 25 km. from Florence at 350 m. a.s.l. and it has a population of about 7,000 inhabitants. It is surrounded by a great variety of landscapes, from the farming plan to the mountain and it houses the Museum of the Life and the Work of Lumberjacks, the church of St. Clemens and St. Francis, Piazza Cavalcanti and Palazzo Stupan.

It halfway position amidst numerous natural tracks allowed the area corresponding to Pelago to be inhabited since Prehistory until the Etruscan-Roman times. It remarkably developed in the Early Middle Ages, when towers and castles began to rise on the numerous reliefs and hills of the territory. Anyway, its toponym derives from the Latin word "pelagus" and it suggests a Roman origin of the first built-up area.
The first documents on Pelago date to 1089. At this time, numerous houses rise around a castle belonging to the Counts Guidi who owned a large area of the Casentino. At that time, the local abbey of Vallombrosa benefited from the donations of this noble family to develop.
As far as the owners of the castle are concerned, the historians harbour many doubts. In effect, many of them think it could have belonged to the family Cattani da Diacceto that were originally vassals of the Guidi. The fortress of Pelago was at the centre of a furious fight between Florence and numerous other people until the Xv century. The Camaldoli, the monks of Camaldoli to whom the Cattani had given the construction in 1207, and the powerful bishop of Fiesole advanced their requests on the fortress. The question was temporarily resolved with the bull issued by Eugene IV, the pope who settled the Cattani were the owners of the castle in 1445.
During the time when the Florentines controlled the Florentine Republic, the territory of Pelago became the "comado" of the big city, namely a centre essentially considered for its fiscal value. Pelago was also involved in the bloody dispute between Guelfs and Ghibellines because of its political dependence upon Florence. The Guelfs, exiled by the Florentines, occupied the castle from 1248 to 1253. Also the sharecropping economy and the architectural development of numerous residences took off in this century and in the following.
During the period of the Cattani, the territory went back into the hands of Florence definitively only in the modern ages. Once it became the chief town in 1808, during the Napoleonic hegemony in Tuscany, Pelago reached its maximum territorial extension during the Restoration, when between 1936 and 1937 it bought numerous places that were previously owned by Regello. Later on, part of the area became part of the town of Ruffia in 1915.