The Hogsmill River in Surrey and Greater London, England is a small chalk stream tributary of the River Thames. It rises in Ewell and flows into the Thames at Kingston upon Thames on the lowest non-tidal reach, that above Teddington Lock. The river is 10 km (6 mi) long and has a catchment area of about 73 km2 (28 sq mi). Nearby land was formerly flood-meadows; following improvements it is now mostly sports grounds, a sewage treatment works and green space, save for Kingston and Epsom town centres. It is a habitat of many animals, fish and insects.