Heathfield Park SSSI is a 41-hectare (100-acre) biological Site of Special Scientific Interest east of Heathfield in East Sussex.

This is a steep valley carved by a stream.

The sheltered wooded habitat has a warm and moist microclimate and it has a number of plant species usually restricted to western Britain, such as Cornish moneywort, hay-scented buckler-fern and the liverwort Frullania tamarisci.

The site is also important for lichens and 76 species have been recorded.

[4] The site is private land with no public access.