Its position on the estuaries of the Stour and Orwell rivers, with its usefulness to mariners as the only safe anchorage between the Thames and the Humber, led to a long period of civil and military maritime significance.

The dockyard built many ships for the Navy, including HMS Conqueror which captured the French Admiral Villeneuve at the Battle of Trafalgar.

1914–1918: Base for the Royal Navy's Harwich Force light cruisers and destroyers under Commodore Tyrwhitt, and for British submarines.

[8] In 1665, not long after the establishment of the Dockyard, a pair of lighthouses were set up on the Town Green to serve as leading lights for ships entering the harbour.

The port is famous for the phrase "Harwich for the Continent", seen on road signs and in London and North Eastern Railway (LNER) advertisements.

The train ferry linkspan still exists today and the rails leading from the former goods yard of Harwich Town railway station are still in position across the road, although the line is blocked by the Trinity House buoy store.

Despite, or perhaps because of, its small size Harwich is highly regarded in terms of architectural heritage, and the whole of the older part of the town, excluding Navyard Wharf, is a conservation area.

[11] The regular street plan with principal thoroughfares connected by numerous small alleys indicates the town's medieval origins, although many buildings of this period are hidden behind 18th century facades.

The house featured in the image of Kings Head St to the left is unique in the town and is an example of a sailmaker's house, thought to have been built circa 1600. Notable public buildings include the parish church of St. Nicholas [12] of 1820-22 (architect: M G Thompson of Dedham[13]), in a restrained Gothic style, with many original furnishings, including a somewhat altered organ in the west end gallery.

The hotel became the Harwich Town Hall, which included the Magistrates Court and, following changes in local government, was sold and divided into apartments.

Also of interest are the High Lighthouse (1818), the unusual Treadwheel Crane (late 17th century), the Old Custom Houses on West Street, a number of Victorian shopfronts and the Electric Palace Cinema (1911), one of the oldest purpose-built cinemas to survive complete with its ornamental frontage and original projection room still intact and operational.

There is little notable building from the later parts of the 20th century, but major recent additions include the lifeboat station and two new structures for Trinity House.

Through concerts, 'singarounds', pub sessions, talks and workshops, the seafaring history and heritage of Harwich is celebrated by local people and international groups.