There is evidence of prehistoric activity in the Harwich area, especially around Dovercourt from the Palaeolithic period onwards. In the Roman period septaria stone was mined at Dovercourt and shipped around the county, and chance Roman finds suggest a sizeable Roman settlement at Dovercourt itself. The place-name evidence suggests that there may have been a temporary army camp at Harwich itself, and there is evidence for an early Saxon burial ground at Dovercourt. Harwich Harbour is mentioned in the documentary references to the Saxon-Viking wars of the ninth and tenth centuries. However, the Domesday Book records Dovercourt, but not Harwich. It is probable that Harwich was not initially regarded as a suitable place for settlement because of its lack of a freshwater supply.
The foundation of Harwich was an economic venture by the Earls of Norfolk in the early thirteenth century, in direct competition with the established market-town and port of Ipswich, further inland on the Orwell river. There is known to have been a chapel at Harwich in 1177, and a town is mentioned in 1229 although a town charter was not granted until 1238. Harwich concentrated on the entrepôt trade, offering a deep-water harbour open at all tides as an alternative to travelling up the tidal Orwell to Ipswich. The town received a second charter in 1318 and a grant of murage to build the town walls in 1338. However the grant was funded by tolls on shipping and infringed on Ipswich’s right to levy tolls on the whole of the Orwell estuary, and was revoked in 1340. Subsequently Harwich received a second murage grant and the town walls were completed. Harwich became an important supply base for ships anchored in Harwich Harbour during the continental campaigns of the fourteenth, fifteenth and sixteenth centuries, and by the fifteenth century there was also a ship-building industry.
In the 1660s Harwich became an important naval base and dockyard. In 1667, because of the Dutch Wars, it was decided to replace the medieval town wall with a turf bank, enclosing both the town and the Navy Yard. The Navy Yard closed in 1713, although ship-building continued on the site under private ownership until 1827. The other industries, such as fishing and trade continued, there was a regular cross-channel service to the Low Counties and in the nineteenth century the septaria mines at Dovercourt were re-opened. The Napoleonic Wars brought further defensive measures to Harwich, including the Redoubt. In the 1890’s the Beacon Hill fort was built and the town was to play an important role as a naval base in both the First and Second World Wars.