an arrondissement in the department of the Drome, in France, 946 square miles in extent. It is divided into nine cantons and 117 communes, and contains 60,518 inhabitants. The capital, a city of the same name, is situated on the right bank of the Drome. It has some silk mills and cloth manufactures, and contains 3421 inhabitants. Near to it is one of the wonders of Dauphiné, the inaccessible mountain, whose base and summit are of the same extent. Long. 5. 13. E. Lat. 44. 44. N.