The Aosta Valley is a mountainous autonomous region in northwestern Italy. It is bordered by Auvergne-Rhône-Alpes, France, to the west, Valais, Switzerland, to the north, and by Piedmont, Italy, to the south and east. The regional capital is Aosta. Covering an area of 3,263 km2 and with a population of about 128,000 it is the smallest, least populous, and least densely populated region of Italy. Italian and French are the official languages, though the native population also speak Valdôtain, a dialect of Franco-Provençal. Italian is spoken as a mother tongue by 77.29% of population, Valdôtain by 17.91%, and French by 1.25%. In 2009, reportedly 50.53% of the population could speak all three languages. The Aosta Valley is an Alpine valley which with its tributary valleys includes the Italian slopes of Mont Blanc, Monte Rosa, Gran Paradiso and the Matterhorn; its highest peak is Mont Blanc (4,810 m or 15,780 ft). This makes it the highest region in Italy by list of Italian regions by highest point.