Southend-on-Sea is a unitary authority and city in the ceremonial county of Essex, England. District with municipality category and comprises the towns of Chalkwell, Eastwood, Leigh-on-Sea, North Shoebury, Prittlewell, Shoeburyness, Southchurch, Thorpe Bay and Westcliff-on-Sea. It is located in the Thames Gateway area, on the north side of the Thames Estuary, 64 km east of central London. It is surrounded on the north by Rochford and on the west by Castle Point. In Southend is the longest pier in the world, known as Southend Pier, by population, is the 36th city of the United Kingdom, with 164,300 registered inhabitants.