Siwa Oasis, oasis in Ma?ru? governorate, western Egypt. It lies near the Libyan frontier, 350 miles (560 km) west-southwest of Cairo. The oasis is 6 miles (10 km) long by 4–5 miles (6–8 km) wide and has about 200 springs. Two rock outcrops provide the sites of the old walled settlements of Siwa and Aghurmi, which are veritable fortresses. The oasis is inhabited by Berber-speaking Sudanic peoples who live in mud-brick houses at the foot of their former strongholds. Ten miles (16 km) northeast is the small oasis of Al-Zaytun (Zeitun), and westward a chain of little oases and small salty pools extends for about 50 miles (80 km). Siwa Oasis is extremely fertile and supports thousands of date palms and olive trees. The export of dates and olive oil provide the chief source of income, supplemented by basketry.