Aglientu is located a few kilometres from the sea, in an area predominantly rich in granite. Its landscape is characterised by majestic boulders and green valleys that slope down towards sandy shores with high desert-like dunes alternating with imposing cliffs. Just like Monti Russu, a pink granite relief with a rounded shape extends towards the Gulf of Asinara. The 22-kilometre-long coastline, with extensive unspoilt stretches, is renowned for the beautiful beaches. Amongst the largest is Rena Majore (on the border of the Santa Teresa Gallura territory), Litarroni and Vignola, a fishing village where a Spanish tower from 1606 stands 12 metres high, from which a panoramic view of the sea and inland can be enjoyed.

The name of the town has Latin roots, with the meaning of white, also being present in other place names in the area (Montagliu, Agliacana, Frati Agli and Agliu). The discovery of stone tools dates the presence of man here since the ancient Neolithic period. Numerous Nuraghes, including Tuttusoni and Finucchjaglia, are mainly distributed along the coast. In Roman times within the area, at the height of the current Aglientu, there was a horse exchange station along the road from Porto Torres to Santa Teresa Gallura. The town centre was built in 1776, when Vittorio Amedeo III ordered the construction of the church of San Francesco d’Assisi. A few decades later, constructions went up in which religious ceremonies, socio-economic activities and trade fairs were held during festivities. Around 1850, a number of wealthy families built houses, establishing the first nucleus of Aglientu, originally a hamlet of Tempio Pausania, before becoming an independent municipality in 1959.

There are numerous town churches: the oldest is the 17th-century one dedicated to San Pancrazio (who is celebrated on 25th January), with much more recent constructions being those dedicated to San Giovanni and San Silverio in the Portobello marina (dating back to the decade of 1930-40). Even more modern, six kilometres from the town, is San Biagio, built in 1967 on the site of a previous edifice, inside which is safeguarded a wooden statue of the saint dating from the 15th to 16th centuries, carved by Sardinian craftsmen. Numerous summer festivals attract thousands of tourists from the coast: an event dedicated to seadas (a sweet cheese with honey) in late June, and to sausage and cheese in mid-August.