ALGECIRAS, or ALGEZIRAS, a seaport of Spain, in the province of Cadiz, 6 miles W. of Gibraltar, on the opposite side of the bay. The town is picturesquely situated, and its name, which signifies in Arabic the island, is derived from a small islet which forms one side of the harbour. It is supplied with water by means of a beautiful aqueduct. It has a dilapidated fortress, and also a military hospital. Though the harbour is bad, and the commerce of the town has considerably declined, there is still a good coasting trade; the exports and imports averaging about X60,000 annually. Charcoal and tanned leather are the chief articles of export. Algeciras was the Portus Albus of the Romans, and the first place in Spain taken by the Moors. It remained in their possession from 713 till 1344, when it was taken by Alphonso XI. of Castile after a celebrated siege of twenty months, which attracted crusaders from all parts of Europe, among whom was the English earl of Derby, grandson of Edward III. It is said that during this siege gunpowder was first used by the Moors in the wars of Europe. The Moorish city was destroyed by Alphonse, and the modern town was not erected till 1760. During the siege of Gibraltar ia 1780-82, Algeciras was the station of the Spanish fleet and floating batteries. Near Algeciras, on 6th July 1801, the English admiral Saumarez attacked a Franco-Spanish fleet, and sustained a reverse; but on the 12th he again attacked the enemy, whose fleet was double his own strength, and inflicted on them a complete defeat. Population, 14,000.