The province of Arezzo or Arretium is the easternmost province in the Tuscany region of northern Italy. Its capital is the city of Arezzo. The province is bordered by the regions of Marche, Emilia-Romagna, Umbria, and the provinces Siena and Florence of Tuscany. It has an area of , a total population of about 347,000 in 37 comuni (singular: comune), and a density of 107.2 people per square kilometer.