Southend-on-Sea, commonly known as Southend, is a coastal city and unitary authority area located in south-eastern Essex, England. Situated on the north side of the Thames Estuary, it lies approximately 40 miles (64 km) east of central London. The city is bordered by Rochford to the north and Castle Point to the west.
The city is recognized as one of the most densely populated places in the United Kingdom outside of London. Notable landmarks include Southend Pier, which is the longest pleasure pier in the world, and London Southend Airport, located to the north of the city centre.