Sassari is an Italian city and the second-largest of Sardinia in terms of population with 120,497 inhabitants as of 2025, and a functional urba…Sassari is an Italian city and the second-largest of Sardinia in terms of population with 120,497 inhabitants as of 2025, and a functional urban area of about 260,000 inhabitants. One of the oldest cities on the island, it contains a considerable collection of art.