Morocco Morocco. Encyclopædia Britannica, Inc. Rabat, Morocco

High Atlas Mountains, Morocco: Tichka Pass

Tichka Pass in the High Atlas Mountains, Morocco.

Anne E. Hubbard/Photo Researchers

East of the Rif and Atlas ranges is the Moulouya basin, a semiarid lowland created by the eroding force of the Moulouya River. Farther east are the High Plateaus (Hauts Plateaux) of eastern Morocco, which lie roughly between 3,900 and 4,250 feet (1,200 and 1,300 metres) in elevation and are extensions of landforms in neighbouring Algeria. The arid regions to the south and southeast of the Atlas constitute the northwestern limit of the Sahara, whereas a narrow transitional band at the base of the mountains is called the pre-Sahara.

Atlantic Morocco consists of plains formed of relatively fine sediments and plateaus of coarser deposits. The Sebou River basin, which lies in the northwest between the Rif Mountains and a line running roughly from Rabat to Fès, is a large alluvial plain. Its agricultural heart is known as the Gharb plain. South of the Rabat-Fès line, between the Atlas and the Atlantic Ocean, are a series of high plains known collectively as the Moroccan Plateau. These include the Saïs Plain near Fès and Meknès, the Tadla Plain to the northeast of Marrakech, the Haouz Plain west of Marrakech, and the broad Chaouïa, Doukkala, and Abda plains south of Casablanca. Between the High Atlas and Anti-Atlas ranges is the Sous River valley. Morocco’s coastline is regular and has few natural harbours. Before modern ports were constructed, sandbars and rocky reefs offshore made navigation difficult.