Portus Magnus

A number of Roman ports were known as portus magnus ("grand port") :
 * Portus Magnus, Spain: modern Almería
 * Portus Magnus, Algeria: modern Bethioua
 * Portus Magnus, Egypt: modern Alexandria
 * Portus Magnus (Mauretania), in the Roman province of Mauretania Caesariensis
 * Magnus Portus: modern Bosham, near Chichester, England