The park was established following campaigns and blockades against logging at Terania Creek, Grier's Scrub and Mount Nardi between 1979 and 1982.

Creating features of gullies, ridges and a massif of peaks that form the eroded remnants of the Tweed shield volcano.

The basalt and rhyolite lava that once flowed from the Tweed volcano (known as Mount Warning), which erupted over 23 million years ago, has produced various vegetation communities.

[4] The beginning of the modern conservation movement involving direct action occurred during 1972 to 1982 in the upper Northern Rivers region.

By 1979 the campaign against logging increased in intensity, starting an event known as the three-year Rainforest War involving a group of dedicated activists being supported by former NSW Premier Neville Wran.

[4] By 1989 UNESCO created world heritage protection for 41 reserves in south-eastern Queensland and north-eastern NSW including the western half of Nightcap.

It has been recognised for its populations of Albert's lyrebird (Menura alberti), green catbird (Ailuroedus crassirostris), pale-yellow robin (Tregellasia capito), Australian logrunner (Orthonyx temminckii), paradise riflebird (Ptiloris paradiseus) and regent bowerbird (Sericulus chrysocephalus).

[19] Another species listed as vulnerable under the TSC Act is the yellow-bellied glider (Petaurus australis) often found in old-growth wet sclerophyll forests.

The rufous bettong (Aepyprymnus rufescens) is a roughly 3 kg marsupial that has significantly declined in range since European settlement.

[23] Another threatened species is the white-eared monarch (Carterornis leucotis), a small bird which relies on insects for the majority of its diet and nests high in the canopy near the rainforest edges.

[24] The marbled frogmouth (Podargus ocellatus), related to the nightjars family, is a threatened bird listed on the TSC Act.

[14] The park contains the largest known population of the threatened Albert's lyrebird (Menura alberti), which is listed on the TSC Act.

The black and yellow bird with a wing span of 30 cm has been for the last two decades the focus of a national conservation effort to save the species from extinction.

[29] The three-toed snake-tooth skink (Coeranoscincus reticulatus) is a borrowing lizard that has a body length of 23 cm and is also listed as vulnerable under the EPBC Act.

15–20 million years old fossil fruits found near Ballarat, Victoria suggest that the genus Eidothea and rainforest were historically widespread.

The following species are all listed as Endangered under the TSC Act: Coast Euodia (Melicope vitiflora), Amyema plicatula, short-footed screw fern (Lindsaea brachypoda), green-leaved rose walnut (Endiandra muelleri subsp.

bracteata), narrow-leaf finger fern (Grammitis stenophylla) and tree guinea flower (Hibbertia hexandra).

The majority of these are listed because of their restricted range, and are threatened by habitat clearing, fragmentation, fire, and local extinction due to small populations and illegal collection.

By 2010 cane toads (Bufo marinus) started appearing around the outside region of the park but in lower numbers than at the nearby Borders Ranges NP.

The cane toad is highly poisonous at every stage of its life, from egg to fully grown, and any animal that tries to eat it would likely die.

Weeds that are becoming a concern at the park include camphor laurel (Cinnamomum camphora), devil's fig (Solanum torvum) and Parramatta grass (Sporobolus africanus).

If a fire did occur it would change habitat conditions and have an adverse impact on threatened rainforest species like the Nightcap oak.

[44][45] On the EPBC Act the disease caused by this pathogen is listed as a key threatening process and has the potential to impact the Nightcap oak.

Ensure that no swimming occurs downstream of Protesters Falls at the park, so that high water quality remains for the threatened Fleays barred frog.

In the park control the dispersal of the introduced Queensland maple (Flindersia brayleyana), a tree that is grown for its timber.