River Mole River Mole The River Mole is a tributary of the River Thames in southern England. It rises in West Sussex near Horsham and flows northwest through Surrey for to the Thames at East Molesey, opposite Hampton Court Palace. The river gives its name to the Surrey district of Mole Valley. The Mole crosses the North Downs between Dorking and Leatherhead, where it cuts a steep-sided valley, known as the Mole Gap, through the chalk. Much of the catchment area lies on impermeable rock (including Wealden Clay and London Clay), meaning that the river level responds rapidly to heavy rainfall. During
River Mole Ages and the river appears as "Amele" in Domesday Book and subsequently as "Emele" in 12th- and 13th-century Court Rolls. This name is probably derived from the Old English word "æmen" meaning "misty" or "causing mists", and the name of the River Ember probably has its origins in this name. The name "Mole" does not appear until the 16th century, first occurring as "Moule" in Harrison's "Description of Britain" of 1577. The antiquarian William Camden uses the Latinized form "Molis" in the 1586 edition of "Britannia" and Michael Drayton is the first to use "Mole" in his poem "Poly-Olbion" published