About 80 km (50 mi) in length and 20 km (12 mi) wide, Siwa Oasis is one of Egypt's most isolated settlements, with 23,000 people, mostly Berbers who developed a unique culture and a distinct language of the Berber family called Siwi.

Its fame lies primarily in its ancient role as the home to an oracle of Ammon, the ruins of which are a popular tourist attraction which gave the oasis its ancient name Ammonium. Historically, it is part of Ancient Libya.

The Siwa oasis is in a deep depression that reaches below sea level, to about −19 metres (−62 ft). To the west the Jaghbuboasis lies in a similar depression and to the east the large Qattara Depression also lies below sea level.