It is the third largest urban area in the Muslim world after Jakarta and Karachi, and the world's 16th largest metropolitan area, consisting of all cities in the Cairo Governorate as well as Giza, 6th of October, Sheikh Zayed City in the Giza Governorate and Shubra El Kheima and Obour in the Qalyubia Governorate, with a total population estimated at 20,500,000 (as of 2012); area: 1,709 km2; density: 10,400/km2.

The Greater Cairo Area and its surrounding region is classified as hot desert climate (BWh) in Köppen-Geiger classification, as all of Egypt. Cairo and its surrounding region have very similar day to day temperatures.

60% of all informal houses in Egypt are located in the Greater Cairo area.