The Faiyum Oasis (Arabic: واحة الفيوم Wāḥat al-Fayyum) is a depression or basin in the desert immediately west of the Nile river, 62 miles south of Cairo, Egypt. The extent of the basin area is estimated at between 1,270 km2 (490 mi2) and 1,700 km2 (656 mi2). The basin floor comprises fields watered by a channel of the Nile, the Bahr Yussef, as it drains into a desert hollow to the west of the Nile Valley. The Bahr Yussef veers west through a narrow neck of land north of Ihnasya, between the archaeological sites of El Lahun and Gurob near Hawara; it then branches out, providing agricultural land in the Faiyum basin, draining into the large saltwater Lake Moeris (Birket Qarun). In prehistory it was a freshwater lake, but is today a saltwater lake. It is a source for tilapia and other fish for the local area

Birket Qarun (Arabic for Lake of Qarun), is located in the Faiyum Oasis and has an abundant population of fish, notably bulti, of which considerable quantities are sent to Cairo. In ancient times this lake was much larger, and the ancient Greeks and Romans called it Lake Moeris.

The valley of Wadi El-Rayan is an area of 1,759 km2 (679 sq mi), 113 km2 (44 sq mi) of which are the dominating water body of the Wadi El Rayan lakes. It is located about 65 km (40 mi) southwest of Faiyum city and 80 km (50 mi) west of the Nile River. The Wadi has been used for man-made lakes from agricultural drainage which has made a reserve of the two separate Wadi El Rayan Lakes. The reserve is composed of a 50.90 km2 (19.65 sq mi) upper lake and a 62.00 km2 (23.94 sq mi) lower lake, with waterfalls between the two. Among the springs, there are three sulphur springs at the southern side of the lower lake, with extensive mobile sand dunes. Wadi El Rayan Waterfalls are considered to be the largest waterfalls in Egypt. At the south and southeast of the springs is Gabal Manqueer Al Rayan, where marine fossils and archeological remains are found. Gabal Madwera, near the lower lake, is known for its extensive dune formations.

No other place in the world yields the number, concentration and quality of such fossils, nor their accessibility and setting in an attractive and protected landscape. The valley was therefore inscribed on the UNESCO World Heritage List in 2005 The fossils found at the site may not be the oldest but their great concentration in the area and the degree of their preservation is such that even some stomach contents are intact. The presence of fossils of other early animals such as sharks, crocodiles, sawfish, turtles and rays found at Wādī al-Ḥītān makes it possible to reconstruct the surrounding environmental and ecological conditions of the time, adding to its justification to be cited as a Heritage site