an arrondissement in the department of the Orne, in the north-west of France, comprehending an extent of 416 square miles, or 266,240 English acres. It is divided into six cantons, in which are 72,418 inhabitants. The capital bears the same name. It stands on the river Sarthe, and contains 13,230 inhabitants, who are employed in manufactures of iron, glass, leather, and some other goods. It is in long. 0. 10. E. lat. 48. 26. N.