At an altitude of 1,890 metres, Lake Naivasha is the highest of the Rift Valley lakes and unique in many ways.  Some 80 kilometres south of the equator and 100 kilometres north-west of Nairobi, Naivasha is approached by a good tarmac road which forms part of the planned trans-Africa highway. This road has replaced the winding trail down the Kikuyu escarpment which was built by Italian prisoners of war in the 1940s.

To the west, the Eburru volcano reaches a height of 2,800 metres and to the north lies the Nyandarua or Aberdare range. To the south is Mt. Longonot, 2,776 metres, with its almost perfectly circular crater. To the south-west the Mau range forms part of the western wall of the Rift.

There was a thriving community around the shores of the lake some four thousand years ago and relics of their lifestyle in the form of knives, axes and arrow heads made from the locally abundant obsidian, or volcanic glass, have contributed much to archaeological knowledge. Later, when the level of the lake fell to expose the Crescent Island or peninsula, a community lived there who left behind many shards of pottery.

Just over a hundred years ago, the Maasai people grazed their cattle in the area and their presence hindered the progress of many of the coastal caravans into the interior, and that of the early European explorers.

The first European to venture into these parts was the German naturalist, G.A. Fischer, who reached the northernmost part of the Ol Njorowa gorge in 1883, followed some months later by the Scot, Joseph Thomson. The volcanic plug in the entrance to the gorge is still called Fischer's column or Fischer's tower, a strange piece of rock inhabited by rock hyrax. Maasai legend tells of a chief's daughter who left home to be married. Against tradition, she turned for one last look at her former home and was immediately transformed into rock, in much the same way as Lot's wife in the Bible.

The name Naivasha comes from the Maasai "enaiposha", meaning approximately "that which is heaving, that which flows to and from". As a description of the water, this is open to many interpretations, but it is perhaps rather an astute way of describing the many moods of the lake.

In the morning, the water can be calm and placid, but afternoon wind can whip up frenzied waves. Also, the water is not seen to go anywhere, as there is no apparent outlet. This is a major oddity and the freshness of the water has been the subject of much study. It is generally thought that underground seepage accounts for it and it is indeed strange that Naivasha is very much freshwater, while other Rift Valley lakes are alkaline. Two rivers, the Melawa and the Gilgil, enter from the north.

The lake has three distinct parts, the main one having a surface area of some 130 square kilometres and a depth of only 8 metres.

On the eastern side, an ancient volcanic crater rim has formed a crescent-shaped peninsula which shelters the Crescent Island crater lake in which the depth approaches 20 metres. Being partly cut off from the main lake, the water here is slightly more saline.

Crescent Island, or peninsula, depending on the water level, is a sanctuary where waterbuck and Thomson's gazelle wander freely.

The third part, Oloiden Bay, is in the south-western section of the basin and is no more than 10 metres deep. Oloiden, or "the small lake", is difficult to approach by boat, due to the number of tree stumps in the water, stretching across from the isthmus originally known as Hippo Point. Today's Hippo Point is further to the north.