Frensham Common is an
English SSSI
heathland of which includes two large lakes. It lies almost wholly within
Frensham,
Surrey, a
nucleated village on
alluvial soil narrowly
buffered to the north-west, connected by a path. The local road network surrounds the site; the nearest trunk roads are away. The elevation is low but undulating with high points near the Kings Ridge - which bisects the common along a north/south axis - at approximately above sea level (ASL) and nearby, to the south-east, the three Devil's Jumps, the highest of which is ASL. The common supports few streams due to the permeability of the soil, although the ground to the south-east, called the Flashes, is boggy. The site supports several protected species, including
sand lizard,
smooth snake,
woodlark,
Dartford warbler and
nightjar. The heathland is at risk of fire when conditions are dry. In 2010, of the common, in very dry conditions, burned. The most recent serious fire was in May 2023 when approximately 10 hectares (25 acres) burnt. The lakes are prone to blooms of
Blue-Green Algae in the summer months. Once detected by the
Environment Agency, the National Trust warns visitors to avoid entering the pond water. ==Lakes==