Carshalton Park is a public park in Carshalton, in the London Borough of Sutton.
The Grotto is situated in the south-east corner of the park. It was built in about 1724 as one of the first features of the ambitious designs for building and landscaping in the park.
A canal, now dry, extends north from the grotto and continues into Carshalton Place. The structure is now in a state of disrepair and access into its interior is normally prevented by locked gates.
It originally had an ornamental iron gate and a marble pavement and roof covered with shells. A branch of the River Wandle used to rise in a subterranean chalk chamber beneath the Grotto, and the river flowed through the centre of the park.