Lake Naivasha is a Ramsar site located in the rift valley region with a size of23, 600 hactares with an Altitude 1,890 meters. This lake lies on the floor of the Rift Valley, 80 km north-west of Nairobi, and consists of a shallow freshwater lake (15,600 hactares) and its fringing Acacia woodland (7,000 ha). Lake Naivasha is of recent geological origin, and is ringed by extinct or dormant volcanoes, including Mountains Longonot, Ol Karia and Eburu. Naivasha's water is supplied by the permanent Malewa and Gilgil rivers, which respectively drain the Aberdare mountains (Important Bird Area KE001) and the Rift Valley floor to the north, by the seasonal Karati river (also draining from the Aberdares) and from substantial ground-water seepage. Naivasha has no surface outlet. The Malewa covers 1,730 kilometers squared of the 2,800 kilometers squared catchment, and contributes 90% of the surface water entering the lake.

It is thought that a combination of underground outflow and sedimentation of salts keeps the lake fresh, unlike other endorheic lakes in the eastern Rift Valley. Naivasha includes three chemically distinct water bodies. The main lake 15,000 hactares, maximum depth 8 m incorporates a partially submerged crater, the Crescent Island lagoon maximum depth 18 meters, at its eastern end. The lagoon is largely isolated at low water levels. To the southeast, separated by papyrus Cyperus papyrus swamp and an isthmus of Acacia woodland, is the small 550 ha, somewhat alkaline Lake Oloidien. Papyrus fringes the main lake's shore with scatterings of other sedges and Typha and cloaks the inlets of the Gilgil and Malewa rivers. There is large floating, wind-driven rafts of the exotic water-hyacinth Eichhornia crassipes, usually concentrated in the south-west sector. Submerged macrophytes (including Potamogeton spp. and Naja pectinata) sometimes occur in large beds, mainly in the shallow eastern part, but these vary greatly in extent.

The shores of Crescent Island lagoon are steep and rocky or flat and muddy, while Oloidien has an open, grassy shoreline, with no emergent or floating macrophytes. The lake's levels fluctuate enormously, and Naivasha has been dry within historic times. The surrounding riparian land is almost all privately owned, much of it now used for intensive horticulture and floriculture using water from the lake. A belt of tall Acacia xanthophloea woodland fringes the lake and extends along the rivers to the north, though portions have been cleared for farming; further from the water this gives way to dry open grassland, Tarchonanthus camphoratus scrub and (on rocky hillsides) Euphorbia forest. Naivasha is the second site listed by Kenya as a Wetland of International Importance under the Ramsar Convention.

The woodland north of the lake and around Lake Oloidien provides habitat for Prionops poliolophus, which has been recorded here regularly and is known to nest. Acrocephalus griseldis is a winter visitor and passage migrant, the exact status of which is unknown. The lake itself supports a diverse water bird community, with more than 80 species regularly recorded during censuses. Depending on water levels, it can be a significant site for Fulica cristata, Platalea alba and Tachybaptus ruficollis. Phoenicopterus minor occurs in small numbers at times, mainly on Oloidien. The lake is known for its high density of Haliaeetus vocifer, which nest in the surrounding Acacia woodland.

Many species of duck and Palearctic waders also occur in numbers, Palearctic duck are especially abundant in November and February. Regionally threatened species include Podiceps cristatus, most recent Kenyan records are from Oloidien; Oxyura maccoa; Anhinga rufa , Casmerodius, Ephippiorhynchus senegalensis, Thalassornis, Porzana pusilla, and Rynchops flavirostris. Lake Naivasha and its surrounding harbour numerous bird species that include kingfishers, pelicans, great cormorants, fish Eagles, Pelicans, Grey-backed fiscal, hawks, cuckoos, woodpeckers, shrikes, Cape Teal, Pied Avocet, Black Heron, Goliath Heron, Maccoa Duck, Great White Pelican, Common Greenshank, Ruff, Green Sandpiper, Hilderbrandt's Francolin, Arrow-marked Babbler, African Fish Eagle, Verreaux's Eagle, Tawny Eagle, Osprey, Hybrid Lovebird, Red-throated Wryneck, Buff-bellied Warbler, Grey Crowned Crane, Black Cuckoo, African Hoopoe, Malachite Kingfisher, Pied Kingfisher, Giant Kingfisher, Greater Flamingo, Lesser Flamingo, Pink-backed Pelican, Pied Avocet, Blacksmith Plover, Coqui Francolin, Hilderbrandt's Francolin, Black Cuckoo, African Cuckoo, Grey-crested Helmetshrike, Cape Teal, Hottentot Teal and Red-billed Teal, Dusky Nightjar, Montane Nightjar, Maccoa Duck, Malachite Sunbird or White-backed Duck.