- Also: Aljazira
- Large port and city in the Gulf of Gibraltar.
- Taken by Castile in 1344 with the aid of a multinational task force of Christian princes and knights.
- Fortified city where Leonor Núñez de Guzmán and several relatives sought refuge after the death of Alfonso XI of Castile, her former lover. They feared acts of revenge by Pedro of Castile, Alfonso's heir. [Pedro, ch.17: 38-52]
- Gómez Carrillo was travelling to Algeciras, believing he had been appointed frontier guard, but the captain of the ship decapitated him by order of Pedro of Castile, and threw his body into the sea. [Pedro, ch. 32: 14-20]