The Crepori River rises in the Serra do Cachimbo at 450 meters, on the border between the municipalities of Itaituba and Jacareacanga. It flows north as an important right tributary of the Tapajos, gathering the Marupa, Creporizinho, and Piranhas rivers along the way. The forest that bears its name stretches across three geological domains: the Southern Para Peripheral Depression in the far north, the Tapajos Residual Plateau through the center and east, and the Amazon Lower Plateau in the south and southwest. Altitudes vary from about 100 meters in the lowlands to considerably higher ground in the southern reaches. The Tapajós Environmental Protection Area borders the forest to the north and east, while the Mundurucu Indigenous Territory presses against its western edge.

Botanists have catalogued 231 taxa across 40 plant families in the Crepori, and what they found underscores both the forest's richness and its mysteries. Orchids dominate with 38 species, followed by 34 species of Araceae and 29 palms. Some species, like the bromeliad Fosteella batistana, are restricted to the alluvial forest along river margins. One species of Aechmea bromeliad has been found in only a single location within the entire forest. The fauna is equally remarkable. Amazon river dolphins and tucuxi inhabit the waterways. The dark-winged trumpeter, Gould's toucanet, and the lettered aracari represent bird species endemic to this stretch of forest. Dense rainforest covers about 88% of the area, with open rainforest accounting for just over 11%, receiving an average of 2,500 millimeters of rain each year.

Created by federal decree on 13 February 2006, the Crepori National Forest occupies a different legal niche than a strict nature reserve or national park. Classified as IUCN Category VI, it permits sustainable use of natural resources, including mining in designated areas. The logic is pragmatic: by allowing controlled extraction, the government hoped to channel activity that would otherwise happen illegally into a regulated framework. ICMBio, the Chico Mendes Institute for Biodiversity Conservation, administers the forest. A consultative council was established in May 2009 to guide management decisions, and by November 2009 a working group began coordinating management tools for the Crepori alongside six other national forests in Para: Amana, Altamira, Jamanxim, Trairao, Itaituba I, and Itaituba II. The management plan was approved in March 2010. Whether regulated extraction can coexist with the extraordinary biodiversity that surveys continue to reveal remains the central experiment of the Crepori's existence.

The Crepori's borders have not held firm. In June 2012, Law 12678 redrew the boundaries of seven protected areas in the region, reducing all but one. The Crepori lost approximately 856 hectares, about 0.2% of its total area, to accommodate the planned Jatoba Hydroelectric Power Plant on the Tapajos River. The original area of 740,661 hectares was trimmed accordingly. It was a small cut in percentage terms, but the precedent it set was larger: protected areas in the Amazon could be reduced by legislative action to make way for energy infrastructure. The same law shrank the neighboring Itaituba I and Itaituba II national forests and the Tapajos Environmental Protection Area. Only the Campos Amazonicos National Park was expanded. For the Crepori, the question is whether these incremental reductions will remain small or whether each one makes the next easier to justify.