The Diano valley area was inhabited by the Ligurian Ingauni tribe, who were stockbreeders and farmers. In Roman times, the woodland was sacred to the goddess Diana and there was probably a temple dedicated to her. In 1772, the valley towns, including Arentino, were amalgamated to form the "Comunitas Diani", which had its own civic statutes and was independent from the Diano manorial administration. Diano Arentino did not actually become a municipality until 1924.

Seen from above, it has the appearance of a number of built-up areas separated by a strip of land on which olive trees are cultivated and which marks the border between the municipal districts. The parish church of Santa Margherita preserves a painting of the Madonna del Rosario. Another picture shows Sant' Antonino and Santa Margherita.

The municipal territory is known for its production of superior-quality olive oil and is composed of two districts: Borrello and Evigno. The district of Diano Borrello was probably founded by the Benedictines, as is suggested by the choice of San Michele Arcangelo as patron saint. The Romanesque church dedicated to the saint preserves a fine sixteenth-century poliptych by Brea.

The town of Evigno lies at the foot of Monte Scortegabecco, which is an attraction for tourists who come to admire the ancient church of San Martino, also probably founded by the Benedictines. The green ridge of Pizzo d'Evigno has been pasture land since time immemorial, as can be seen from the numerous "caselle" (rustic dry-stone buildings), the earliest dwellings of the Ingauni. A further sign of early settlement in the Pizzo d'Evigno area are the three "neviere": man-made cavities surrounded by dry-stone walls that were once used for catchment and storage of snow and ice.