The River Lee or River Lea is a river in England. It begins in Leagrave Park, Leagrave, Luton in the Chiltern Hills. It flows generally southeast, east, and then south to London where it meets the River Thames. The last section is known as Bow Creek. A section of the river runs through Hertford castle and shares a valley with the river Beane at Hartham common. Morgans School, in Hertford, have named one of their houses after the river Lea.