Alt Pirineu i Aran is one of the seven vegueries defined by the Regional Plan of Catalonia. It is located in the Catalan High Pyrenees .It is formed by six comarques : Alt Urgell, Alta Ribagorça, Baixa Cerdanya, Pallars Jussà, Pallars Sobirà and Val d'Aran. Val d'Aran has an autonomous government called Conselh Generau d'Aran.The veguerie of Alt Pirineu i Aran is the largest territory, with 18% of Catalonia's total surface area, but the one with the least population , with a density of 12.2 inhabitants/km2 .VeguerieThe Veguerie was an important feudal land division in the Principality of Catalonia, the Kingdom of Sardinia, and the Duchy of Athens during the Middle Ages until the Nueva Planta decrees of 1716. It was the primary division of a county in Catalonia and the basic territorial unit of government in Sardinia and Athens after those countries became part of the Crown of Aragon. The office of a veguer was called a vigeriate .