The park conserves three endangered ecological communities, including an area of rainforest at Bunga Head, and provides habitat for three endangered bird species and for 19 vulnerable animals. It also contains fossils from the Devonian period and most of the catchment of Nelson Creek, which is the principal tributary of Nelson Lagoon.
Mimosa Rocks National Park also contains places of cultural significance to local Aboriginal people, and evidence of past pastoral, timber harvesting, gold mining and recreational ventures. A local tradition of philanthropy, in which a number of neighbouring property owners have donated their land to the park, is a unique feature of this park.
