Plymouth (i/ˈplɪməθ/) is a city on the south coast of Devon, England, about 37 miles (60 km) south-west of Exeter and 190 miles (310 km) west-south-west of London, between the mouths of the rivers Plym to the east and Tamar to the west where they join Plymouth Sound to form the boundary with Cornwall. In what body of water do the rivers Tamar and Plym converge