A town of northern France in the department of Nord, 34 m. N.W. of Lille by rail. Pop. (1906) 1844. It stands on an isolated hill (515 ft.) from which portions of France, Belgium and England can be seen, with 32 towns and ioo villages, including St Omer, Dunkirk, Ypres and Ostend. The former hotel de vine (1634), the hotel de la Noble Cour, once the seat of the jurisdiction of maritime Flanders, now the town-hall, and the hotel des ducs d'Halluin are the historic buildings of the town. Cassel has a communal college. Its industrial establishments include tanneries, oil-mills, salt refineries and breweries, and there is trade in cattle and butter.
The town, supposed to occupy the site of Castellum Menapiorum, was a Roman station, as numerous remains of the Gallo-Roman period attest, and an important centre of roads. It is frequently mentioned in the wars of the middle ages, and was the scene of important battles in 1071, when Robert, count of Flanders, vanquished his rival Arnulf; 1328, when Philip of Valois defeated the Flemish; and 1617, when William of Orange was defeated by Philip, duke of Orleans, brother of Louis XIV. General D. R. Vandamme (1770-1830) was born in the town.