Town Common SSSI covers an extensive tract of lowland heathland centred on a hilly ridge separating the floodplain of the Avon Valley from the Moors River. Exposures of the deposits forming this ridge are of special geological interest. The topography is diverse, and with variations in the underlying geology and drainage conditions, there is a varied mosaic of heathland plant communities. Areas of succession from open heath to conifer and mixed woodland add further interest. The heathland is especially valued for a wide assemblage of bird, reptile, dragonfly and other invertebrate species distinctive to this habitat, including several that are nationally rare or scarce. Further heathland, wet grassland and other wetland covered by the adjoining Avon Valley, Moors River and Hurn Common SSSIs place Town Common within an exceptionally large tract of such habitats for lowland Britain. This entire area has a national and international importance for its wildlife interest.