Southend-on-Sea, commonly referred to as Southend, is a coastal city and unitary authority area in south-eastern Essex, England. It lies on the north side of the Thames Estuary, 40 miles (64 km) east of central London. It is bordered to the north by Rochford and to the west by Castle Point. The city is one of the most densely populated places in the country outside of London. It is home to the lon…