Sr, an arrondissement of the department of the Pas de Calais, in France. It extends over 450 square miles, and comprises seven cantons and 136 communes, with 105,020 inhabitants. The capital is the city of the same name, situated on the river Aa. It has walls, broad streets, and well-built houses, a cathedral, six churches, a college, 2100 houses, and 19,032 inhabitants. It is a place of considerable manufactures of woollens, and where, by means of a canal connecting it with the city of Calais, there is a great internal trade in agricultural products. Long. 2° 9'. 52". E. Lat. 50° 44'. 52". N.