Calais, a seaport and manufacturing town of northern France, in the department of Pas-de-Calais, 18 m. E.S.E. of Dover, and 185 m. N. of Paris by the Northern railway. Pop. (1906) 59,623. Calais, formerly a celebrated fortress, is defended by four forts, not of modern construction, by a citadel built in 1560, which overlooks it on the west, and by batteries. The old town stands on an island hemmed in by the canal and the harbour basins, which divide it from the much more extensive manufacturing quarter of St Pierre, enveloping it on the east and south. The demolition of the ramparts of Old Calais was followed by the construction of a new circle of defences, embracing both the old and new quarters, and strengthened by a deep moat. In the centre of the old town is the Place d'Armes, in which stands the former hôtel-de-ville (rebuilt in 1740, restored in 1867), with busts of Eustache de St Pierre, Francis, duke of Guise, and Cardinal Richelieu. The belfry belongs to the 16th and early 17th century. Close by is the Tour du Guet, or watch-tower, used as a lighthouse until 1848. The church of Notre-Dame, built during the English occupancy of Calais, has a fine high altar of the 17th century; its lofty tower serves as a landmark for sailors.

A gateway flanked by turrets (14th century) is a relic of the Hôtel de Guise, built as a gild hall for the English woolstaplers, and given to the duke of Guise as a reward for the recapture of Calais. The modern town-hall and a church of the 19th century are the chief buildings of the quarter of St Pierre. Calais has a board of trade-arbitrators, a tribunal and a chamber of commerce, a commercial and industrial school, and a communal college.

The harbour is entered from the roads by way of a channel leading to the outer harbour which communicates with a floating basin 22 acres in extent, on the east, and with the older and less commodious portion of the harbour to the north and west of the old town. The harbour is connected by canals with the river Aa and the navigable waterways of the department.

Calais is the principal port for the continental passenger traffic with England carried on by the South-Eastern & Chatham and the Northern of France railways. The average number of passengers between Dover and Calais for the years 1902-1906 inclusive was 315,012. Trade is chiefly with the United Kingdom. The principal exports are wines, especially champagne, spirits, hay, straw, wool, potatoes, woven goods, fruit, glass-ware, lace and metal-ware. Imports include cotton and silk goods, coal, iron and steel, petroleum, timber, raw wool, cotton yarn and cork. During the five years 1901-1905 the average annual value of exports was £8,388,000 (£6,363,000 in the years 1896-1900), of imports £4,145,000 (£3,759,000 in 1896-1900). In 1905, exclusive of passenger and mail boats, there entered the port 848 vessels of 312,477 tons and cleared 857 of 305,284 tons, these being engaged in the general carrying trade of the port. The main industry of Calais is the manufacture of tulle and lace, for which it is the chief centre in France. Brewing, saw-milling, boat-building, and the manufacture of biscuits, soap and submarine cables are also carried on.

Deep-sea and coast fishing for cod, herring and mackerel employ over 1000 of the inhabitants.

Calais was a petty fishing-village, with a natural harbour at the mouth of a stream, till the end of the 10th century. It was first improved by Baldwin IV., count of Flanders, in 997, and afterwards, in 1224, was regularly fortified by Philip Hurepel, count of Boulogne. It was besieged in 1346, after the battle of Crécy, by Edward III. and held out resolutely by the bravery of Jean de Vienne, its governor, till after nearly a year's siege famine forced it to surrender. Its inhabitants were saved from massacre by the devotion of Eustache de St Pierre and six of the chief citizens, who were themselves spared at the prayer of Queen Philippa. The city remained in the hands of the English till 1558, when it was taken by Francis, duke of Guise, at the head of 30,000 men from the ill-provided English garrison, only 800 strong, after a siege of seven days. From this time the Calaisis or territory of Calais was known as the Pays Reconquis. It was held by the Spaniards from 1595 to 1598, but was restored to France by the treaty of Vervins.