Map - Mostaganem

Mostaganem (Mustɣanem; مستغانم) is a port city in and capital of Mostaganem province, in the northwest of Algeria. The city, founded in the 11th century lies on the Gulf of Arzew, Mediterranean Sea and is 72 km ENE of Oran. It is considered as the second-largest city in the country's northwest, after Oran, and as Algeria's fourth-largest port city with its 457.986 inhabitants as of the 2018 census.

The city was founded in the 11th century as Murustage but has origins going back to Punic and Roman times. In 1516, it was captured by the Ottoman admiral Barbarossa and became a centre for Mediterranean sea corsairs, as well as a commercial port. By 1700, it had come under Ottoman rule. In 1833, the city was taken by France and a garrison established. Algeria became independent in 1962.

Mostaganem corresponds to the ancient Punic port of Murustaga. After becoming part of the Roman Empire, it was, according to some sources, officially renamed Cartennae under the emperor Gallienus (253–268). However, according to more weighty sources, Cartennae (or Cartenna or Cartennas) corresponds instead to modern Ténès, 50 km to the east. In any case, Murustaga is the name by which the town was known when it became a Christian bishopric, and by which it is referred to in the Catholic Church's list of episcopal sees. It also underlies the modern name of Mostaganem.

The town was ruled by the Zirid dynasty between 973–1146. Then, it was conquered by the Almoravid dynasty, and reached its high point of power under Yusuf ibn Tashfin (c. 1061–1106). Mostaganem was later ruled by the Zayyanid dynasty of Tlemcen and it was conquered again by the Marinid dynasty of Fes. After that the Zayyanid dynasty took control of the city again. In the 16th century, the town resisted a Spanish invasion and came under the power of the Ottoman Hayreddin Barbarossa.