The name derives from "Castellari, fortifications built by the ancient Ligurian in high locations. A fortified mansion was transformed into a castle by the family Quaranta and around this, the town began to develop. Town in the province of Imperia, situated on a hill, East of the valley Argentina, near Taggia and Riva Ligure. It is surrounded by thick vegetation and the inhabitants are mainly devoted to the cultivation of flowers, olives and vines. The main centre is similar to those of other towns in Liguria, with characteristic narrow streets and steep staircases, often dominated by the typical arches that support the buildings that face each other.
The first official mention on Castellaro, dates back to 1153, in a deed regarding the sale of a land estate by the Marquis of Clavesana to Anselmo Quaranta. In 1228 the Republic of Genoa officially assigned the fief and the surrounding territories to Bonifacio Lengueglia, whose successors in the XV century, divided the lands of Castellaro into two shares and sold them to the Anfreone brothers. In the second half of the XVI century, left without any defense by Lord Spinola, residents in Genoa, the town was attacked by Saracen pirates who pillaged and killed or kidnapped the inhabitants. In the following centuries it was the object of bitter disputes among the heirs of the Spinola until the end of the XVII century, a period which it passed to the domains of Marco Antonio Gentile and his wife Maria Brigida Spinola and remained so, until the conquest by Napoleon in 1797.
After the fall of the French and the Congress of Vienna, Castellaro was incorporated in the Kingdom of Sardinia and from 1861 in the Kingdom of Italy.

Not to miss:
The sanctuary of Nostra Signora di Lampedusa, which can be reached by a road signed by fifteen niches of the Cross. It was built in the XVII century.
The Parish Church of St. Peter in Chains from the XVII century. It houses the high altar and the tabernacle of marble by the sculptor Gaggini, another eight altars of great value and a wooden statue of the Assumption of Anton Maria Maragliano.
The Old Chapel preserves candlesticks and sacred objects dating from the XVII century and an old painting of St. Eligius.
Palace Arnaldi, flanked by two side towers in neo-Gothic style in the heart of old centre. The building dates back to the XIX century and is entitled to the Bishop Arnaldi, archbishop of Spoleto.
Palace of the Gentile Family.
The castle of which remains only part of the semicircular tower.