Black Firs and Cranberry Bog is a nature reserve of the Staffordshire Wildlife Trust, adjacent to Balterley Heath and about 1 mile (1.6 km) north of the village of Betley, in Staffordshire, England.

[1] About 7,000 years ago, the site of Black Firs was a lake about 2 metres deep, left by retreating glaciers of the last ice age.

[1] By 1800, drainage ditches had been created, in a pattern of concentric rings, and trees had been planted.

Black Mere is the remaining part of the original kettle hole lake.

[1] Black Firs, which has been drained in the past, continues to dry out, and the hydrological link with Cranberry Bog is not well understood, so that the consequence of any raising of water levels is unclear.