an arrondissement of the department of the Pas de Calais, in France. It extends over 490 square miles, and is divided into six cantons, which are subdivided into 142 communes, having a population of 72,800 persons. The capital is of the same name, and stands on the left bank of the river Canche, eight miles from the sea. It contains 840 houses, and 3560 inhabitants, who subsist in part from trading in leather and linen, and refining sugar and tunnery, and in part from the custom of travellers passing through it in the way between Calais and Paris.