The park is located in the provinces of Manu and Paucartambo (Departments of Madre de Dios and Cuzco respectively), comprising lands on the eastern slopes of the Andes and on the Peruvian Amazones. The limits to the north are the watershed separating the catchments basins of Manu and de las Piedras rivers (72° 01'W, 11° 17'S); to the south the area where the road from Paucartambo to the north-west turns to Tres Cruces (71° 30'W, 13° 11'S); to the east the region on the left margin of the Alto Madre de Dios River to the Pilcopata River, Department of Cuzco (71° 10'W, 12° 18'S); and to the west the watershed separating the catchment basins of the Manu and Camisea Rivers - also the limit between the Departments of Cuzco and Madre de Dios (72° 22'W, 11° 45'S).
Intangible area, protection of the fauna and flora, and of the Andean oriental and Amazon scenic beauties, it embraces territories from the Andean puna and yunga in the department of Cuzco to the low jungle in the department of Madre de Dios, furrowed by the Manu river, high part of Madre de Dios river and affluent.
Most of its extension is located in the area of low jungle, between the 200 and 400 meters above sea level (656 and 1312 feet). The rivers of the wild area can be navigated in small crafts in any time of the year.
It integrates elements of exceptional beauty and scientific interest, harboring more than 5,000 species of mammals and more than 1 million species of insects and spineless.
With a park the size of Manu, with a wide range of altitude, vegetation varies widely, however the most widespread vegetation types found are tropical lowland rainforest, tropical montane rainforest and Puna vegetation (grasslands). The lowland forests occur on the alluvial plains and the interfluvial hills. Those on the hills may experience seasonal water supply, given the monthly variation in rainfall, while the forests on the alluvial plains are likely to be seasonally flooded. The montane forests experience less variation in the water supply and are exposed to lower temperatures. The management plan (La Molina, 1986) maps 14 forest types using the Holdridge system (after Tosi, 1960), although, given the lack of rainfall data, this must be to some extent speculative. Despite the high diversity of plant species in this region, the flora of Manu is still poorly known and floristic inventories must be considered as preliminary (Gentry, 1985). The few collections of plants are those of Foster (1985) and Gentry (1985) made in the alluvial plains near the Biological Station, and in the Tres Cruces region of the uplands. Other collections have been made by Terborgh (1985) and Janson (1985) on trees where birds and primates obtain food. Despite this, in the last ten years, 1147 plant species have been identified in the park within quite a small area (500 ha), and it is likely that the number of species to be found within the park is well over this figure. More recent data (Saavedra, 1989) indicate 1,200 lowland vascular species and a single one hectare plot near the Cocha Cashu research station supported more than 200 tree species.
In a hectare plot on the alluvial plains, 17 trees with a diameter of more than 70 cm were found (4 to 11 trees with such a diameter would be more usual). The biggest tree was a Ceiba pentandra (120 cm), while others included the locally rare Poulsenia armata (110 cm) and Calycophyllum sp. (117 cm), and locally endangered Swietenia macrophylla (105 cm) and Dipteryx odorata (100 cm). The most common tree in the plot was Otoba parviflora (IK), and other highly abundant species included palms of the genera Astrocaryum, Iriartea and Scheelea, two species of Quararibea (Bombacaceae), Guarea and Trichilia (both Meliaceae from the subcanopy), one Pouteria (Sapotaceae), Pseudolmedia laevis (Moraceae) and Theobroma cacao (Sterculiaceae). Another striking feature of these forests is the high abundance of Ficus sp., of which there are at least 18 species - only 15 Ficus species are mentioned in the Flora of Peru (Standley, 1937). Lianas are common, and 79 lianas of 43 species were found within 1,000 sq.m. With the current knowledge of the flora of the park it is not possible to give a detailed account of threatened, endemic or potentially economically important species. Swietenia macrophylla and Cedrela odorata which grow in almost pure stands, are two of the species economically important for their wood, while Theobroma cacao and Quararibea cordata (IK) are both cultivated for their fruits outside the park.
A total of more than 800 bird species (Saavedra, 1989) and 200 species of mammals has been identified, 500 birds alone from the lowland forests around Cocha Cashu Biological Station, and the check lists of Terborgh, Janson and Brecht (1984) give habitats, foraging position, activity (sociability) and abundance for all birds and mammals found up to 1982. The bird species found in Manu represent 25% of all the birds known in South America and 10% of all the species in the world and it is thought that there may be as many 1,000 bird species in total. According to Renton (1990), six species of macaw occur in the lowland forest, Ara ararauna, A. chloroptera, A. macao, A. severa, and A. manilata.
Three Endemic Bird Areas are represented within the park, the South-east Peruvian lowlands (B30), home to 15 restricted range species, the Eastern Andes of Peru (B29), with 11 restricted range species, and the Western Andes of Peru (B27) with 30 restricted range species (ICBP, 1992).
There are 13 species of monkey, and it is estimated that there are over 100 species of bat. There are also 12 species of reptiles within 7 families (UNA-CEPID, 1986), and 77 species of Amphibian from fire families are known for the Cocha Cashu area (Rodriguez, in press).
There are no check lists available for invertebrates, although it has been estimated that the park contains around 500,000 species of arthropod. Again, most of the information has been gathered in the lowlands, and little detailed information is available on mountain fauna. Species known to be globally threatened which occur in the park include woolly monkey Lagothrix lagotricha, Emperor tamarin Saguinus imperator, giant otter Pteronura brasiliensis (VU), giant anteater Myrmecophaga tridactyla (VU), giant armadillo Priodontes maximus (EN), ocelot Felis pardalis, Andean cat Oreailurus jacobita (VU), jaguar Panthera onca, small-eared zorro Atelocynus microtis (DD), bush dog Speothos venaticus (VU), North Andean Huemul Hippocamelus antisensis (DD), spectacled bear Tremarctos ornatus (VU), crocodile Crocodilus crocodilus, and black caiman Melanosuchus niger (EN).
Fish species identified by Groenendijk and Hajek (1995) which are eaten by the local poplulation include gamitana Colossoma macroponum, paco Piaratus brachypomus, red-tailed sabalo Brycon erythropterum, boquichico Prochilodus nigricans, lisa Leporinus trifasciatus and lisa Schizodon fasciatus.