Southend-on-Sea, commonly referred to as Southend, is a coastal city and unitary authority area with borough status in southeastern Essex, England. It lies on the north side of the Thames Estuary, 40 miles east of central London. It is bordered to the north by Rochford and to the west by Castle Point. It is home to the longest pleasure pier in the world, Southend Pier. London Southend Airport is located north of the city centre.