Headon Warren and West High Down is a 276.3-hectare (683-acre) Site of Special Scientific Interest (SSSI) located at the westernmost end of the Isle of Wight.

[1] Headon Warren is an example of a lowland acid heath and West High Down and Tennyson Down are chalk ridges with a rich calcareous grassland community; the close proximity of these two different plant communities in a maritime setting is of scientific interest.

[1] The chalk downland has a typical flora of calcareous maritime grassland, with nine species of orchids and large populations of such rare plants as early gentian and tufted centaury.

On the cliffs, the rare plants hoary stock and rock samphire grow.

Breeding birds on the cliffs include herring gull, fulmar, kittiwake, cormorant and shag, with smaller populations of razorbill, puffin and guillemot, and the peregrine falcon also breeds here.