Plymouth is a city and unitary authority area on the coast of Devon, England, about 190 miles (310 km) south-west of London. It is built between the mouths of the rivers Plym to the east and Tamar to the west, where they join Plymouth Sound. Since 1967 the City of Plymouth has included the suburbs of Plympton and Plymstock, which are on the east side of the River Plym.