Chadwell-St-Mary is in the
unitary authority of
Thurrock in Essex, England. It is one of the
traditional (Church of England) parishes in Thurrock and a former
civil parish. Its residential areas are on the higher ground overlooking the former Thameside marshland.
Grays is a town centred west of it. Closer still, south is the modern town of
Tilbury which was almost wholly part of the parish until the end of the 19th century. The settlement is frequently referred to simply as
Chadwell, particularly before the 19th century.