Carshalton Ponds are located in the centre of old Carshalton, a village on the north side of the Chalk Downs, in the valley of the River Wandle. The ponds date back for centuries and were probably the reason for an early Saxon settlement in the area. The ponds were once a single pond, but were divided into two pools in the 15th century - one for the public and one private, for Stone Court and then The Grove. The lower east pond was used as a reservoir for Carshalton's upper mill, which ground corn for the village. The ponds were powered by a series of springs and streams. Today, the ponds are kept topped up artificially, as they would have dried up otherwise. They are surrounded by several listed structures, such as a road bridge, culverts, retaining walls and buildings. The ponds are a starting or finishing point for the Wandle Trail, a 12-mile walking and cycling route that follows the River Wandle from Croydon to Wandsworth.