When Europeans settled in Manning Valley, the area was occupied by Aboriginal people: the Biripi Nation. This Aboriginal nation is made up of small groups of mostly one or two families, who travelled their country as availability to food sources changed with the seasons. The Biripi harvested native plants, each for a specific use. Identify their food plants, medicinal plants, arts/crafts plants and cultural plants when you visit Brimbin with the help of the Biripi Nation website.

Manning Valley has over 260 different species of bird, many of which inhabit Brimbin, making it an ideal spot for bird watching. Nests can be seen along waterways. Due to the range of plant communities within the reserve and its proximity to the coast, waterbirds, raptors, woodland and seabirds can be seen at Brimbin. This includes the largest owl on the Australian continent: the powerful owl.

The name 'Brimbin' comes from a local Aboriginal word for 'stringybark', which are common to the reserve, as are white mahogany, tallowwood and turpentine. Narrow-leaved red gums provide important food and habitat for koalas. Grey myrtle, swamp oak and water gum can be found along the waterways, with mangroves lining the banks below the tidal limit. River mangrove is usually a bushy shrub, with elongated fruit and clustered white flowers that smell like banana. Its main identifying feature is salt encrustation on its spoon-shaped leaves. Grey mangroves grow, in this area, to around 10m, and have oval pointed leaves, pale green flattened fruit and spongy pencil-like aerial roots spreading from the base of the trunk.

The Travelling Stock Route (TSR) in Australia is an authorised thoroughfare for walking domestic lifestock between locations, and these routes are collectively known as 'The Long Paddock'. Parts of Brimbin were originally the TSR of a stock camp sold in the 1960s. Old Port Macquarie Road, now part of Ms Kellys walking track, follows a section of track established in the 1820s linking Port Macquarie to the Australian Agricultural Co. lands at Stroud and Gloucester. The route allowed bullock-drawn carts to cross Dawson River.