Tonbridge ( TUN-brij) is a market town in Kent, England, on the River Medway, 4 miles (6 km) north of Royal Tunbridge Wells, 12 miles (19 km) south west of Maidstone and 29 miles (47 km) south east of London. In the administrative borough of Tonbridge and Malling, it had a population of 40,356 in 2015.