Longmoor Bog is a 14-hectare (35-acre) biological Site of Special Scientific Interest north of Finchampstead in Berkshire.

[1][2] An area of 11.8 hectares (29 acres) is a Local Nature Reserve.

It is part of California Country Park, which is owned and managed by Wokingham District Council.

A small stream runs through the carr woodland, which has peat to a depth of more than a metre and the ground is covered by mosses.

The wet heath is important for insects, such as the bog bush cricket, silver-studded blue butterfly, emperor dragonfly, waved black moth and wood ant.