The area of Folkestone has been occupied since at least the Neolithic, being the shortest crossing point from France. The East Cliff area has recently been excavated and produced finds from the Paleolithic period through to the Roman Era, when settlement moved to the Bayle area of the town. On the East Cliff there was an extensive Iron Age settlement and harbour which, amongst other industry, produced thousands of quernstones over at least 200 years and traded with the near continent for many commodities including pottery, wine and quernstones. A Roman style villa was constructed in approximately AD100 followed by a more extensive one in about AD200, which was subsequently abandoned in c.AD350.
A Norman knight held a Barony of Folkestone, by which time the settlement had become a fishing village. That led to its entry as a part of the Cinque Ports in the thirteenth century and with that the privilege of being a wealthy trading port. At the start of the Tudor period it had become a town in its own right. Wars with France meant that defences had to be built here and soon plans for a Folkestone Harbour began. Folkestone, like most settlements on the south coast, became involved in smuggling during the eighteenth century. At the beginning of the 1800s a harbour was developed, but it was the coming of the railways in 1843 that would have the bigger impact. With it came the tourist trade, and the two industries contributed to its prosperity until changes in tourist opportunities in the mid twentieth century hollowed out its economy.
Until the 19th century Folkestone remained a small fishing community with a seafront that was continually battered by storms and encroaching shingle that made it hard to land boats. In 1807 an Act of Parliament was passed to build a pier and harbour which was built by Thomas Telford in 1809. By 1820 a harbour area of had been enclosed. Folkestone's trade and population grew slightly but development was still hampered by sand and silt from the Pent Stream. The Folkestone Harbour Company invested heavily in removing the silt but with little success. In 1842 the company became bankrupt and the Government put the derelict harbour up for sale. It was bought by the South Eastern Railway Company (SER), which was then building the London to Dover railway line. George Turnbull was responsible in 1844 for building the Horn pier. Dredging the harbour, and the construction of a rail route down to it, began almost immediately, and the town soon became the SER’s principal packet station for the Continental traffic to Boulogne.
Folkestone Harbour Company commissioned Foster Associates to produce a masterplan for Folkestone which was published in April 2006. The plans describe the rebuilding of the harbour as a marina, a "Green Wave" along the sea front linking countryside west and east of the town, new housing, shops, a performance area and small university campus. The plans take in the land that was previously the Rotunda Amusement Park. Progress in developing the area has been inhibited by the recession and by new guidelines governing flood protection. A new approach to the seafront is being developed by Terry Farrell and Partners, and the former fairground site is being considered for temporary recreational use whilst planning takes place.
However, there is an alternative plan being developed by the Remembrance Line Association which is based on retaining the harbour railway and its station as a major heritage/tourist operation and 'Leaving for War' museum given the significance of the Folkestone Harbour Branch in both World Wars which is important to the Allied and Commonwealth nations. The harbour railway station, now unused, is gradually succumbing to nature.
Although Kent was the first part of the British mainland to be conquered and settled by the invading Angles, Saxons and Jutes from the middle of the 5th century AD onwards, after the departure of the Romans, it was not until the late 7th century that the spelling Folcanstan appears. One suggestion is that this refers to Folca's stone; another suggestion is that it came from an Old English personal name, with the addition of stone, possibly meaning, in this context, "meeting place". It was not until the mid 19th century that the spelling of "Folkestone" was fixed as such, with the Earl of Radnor requesting that the town's name be standardised (although this tendency towards standardisation in the 19th century is true of English place names generally). Folkestone is often misspelt, variants including Folkston, Folkstone & Folkeston.