The town is located at the foot of Mount Limbara in the province of Olbia-Tempio. Some scholars believe that the place name derives from the Greek word Oskiros, fortress.
After Roman domination, during which a castrum was built to defend against Corsican and bailiff invasions, in the Middle Ages it came under the curatorship of Monte Acuto. In the 11th century it was endowed with an imposing castle, in which Adelasia of Torres signed the deed donating the giudicato to the pontiff in case she died without heirs. With the end of the giudicato, however, it passed into the hands of several lordships, the Doria, Malaspina, Giudici d'Arborea and Aragonese. The latter two families disputed it for a long time, until in the 18th century it became the possession of the Tellez-Giron.
In the mid-19th century it appeared as one of the richest regions in the whole of Sardinia. Thanks to the construction of the railroad, it found itself for a long time at the center of the two most important communication routes that connected the north coast with the rest of the island. In 1927 the construction of the dam on the Coghinas River and the lake of the same name led to the birth of one of the first industrial experiences in northern Sardinia.