The Dark Glen is so called because of the shadow cast by Sileau Curn. The area is managed by the Manx Wildlife Trust, protecting the Lemon scented Fern which grows along the river together with Common Spotted Orchid, Aspen which can be found together with Hen harriers and Stonechats.
A farm settlement used to exist in the Glen up until the late 1800s. High up on the hills are hut circles from when animals were taken up to high pasture in the summer. The remains of an old mill and dam can still be seen together with a Tholtan known as The Phurt next to the stream.