The East Sussex town famous for its Guy Fawkes Night celebrations is Lewes. Its annual Lewes Bonfire is one of Britain’s largest and most elaborate 5 November events, combining torchlit processions, bonfires, fireworks and burning effigies.
Lewes’s tradition is broader than a simple commemoration of the failed Gunpowder Plot of 1605. The festivities also remember 17 Protestant martyrs from the town who were burned during the Marian Persecutions under Mary I. That local history helps explain the event’s distinctive religious symbolism, including burning crosses and memorial ceremonies.
The celebrations are organised by several local bonfire societies, each with its own procession and fire site. Groups from elsewhere in Sussex also travel to Lewes, producing exceptionally large crowds for a town of its size.
Eastbourne, Hastings and Brighton are all East Sussex or nearby coastal places, but they are not the canonical answer to this question. Lewes is the town most strongly associated with England’s Bonfire Night tradition.