AlgheroCatalan and S'Alighera in Sardinian), is a town of about 35,000 inhabitants. It lies in the province of Sassari in north-eastern Sardinia, Italy.
It is the historical centre. The people speak an ancient Catalan dialect because Catalan invaders repopulated the town after expelling the autochthonous Sardinian population in 1372, following several revolts. Catalan was replaced as the official language by Spanish in the 17th century, then by Italian. In the 1990s about 60% of locals still understood spoken Algherese Catalan.