The Giudicato of Arborea (, ) was one of the four independent, hereditary "judicatures" (giudicati) into which the island of Sardinia was divided in the High Middle Ages. It occupied the central-west portion of the island, wedged between Logudoro to the north and east, Cagliari to the south and east, and the Mediterranean Sea to the west. To the north west and beyond Logudoro was located Gallura, with which Arborea had far less interaction. Arborea outlasted her neighbours, surviving well into the 15th century. The earliest known judicial seat was Tharros (Tarra). Giudicato of Arborea at the times of its maximum expansion occupied the whole island's territory, except the cities of Alghero and Cagliari.