an arrondissement of the department of the Upper Alps, in France, 658 square miles in extent, containing five cantons, twenty-seven communes, and 82,370 inhabitants. The chief place, a city of the same name, stands in an alpine situation on the river Durance, and is strongly fortified, having been considered as the key of the gate between France and Italy. It contains only 2976 civil inhabitants. Long. 6° 39' E. Lat. 44° 64' N.