A light industrial town situated in the Pays de Caux by the banks of the Seine and Lézarde rivers, some 6 miles (9.7 km) east of Le Havre, at the junction of the N282, D231 and D9015 roads.

Sir John Fastolf of Caister Castle Norfolk (1380–1459) later claimed to have been 'the first man over the side' of the boat when the English landed outside the town; and he certainly played a part in the siege, being invalided home afterwards.

The Siege of Harfleur lasted some weeks longer than Henry V had anticipated; that was not helped by the outbreak of dysentery which afflicted and killed soldiers, knights, and nobles, with many of the sick having to be transported back to England.

The French cut off the English route and confronted them on the muddy fields near Azincourt (not the present-day Agincourt) on Saint Crispin's Day, 25 October 1415.

In 1884, Forges et Chantiers de la Méditerranée shipbuilding company constructed an artillery workshop on the land immediately south of the canal, Gustave Canet [fr] known for his QF designs worked there.

In January 1897 the workshop together with the shipyard's intellectual property related to artillery was bought by Schneider et Cie, who employed Canet and invested a lot of money into developing the facility into a full-scale plant with a large testing range that could be used for firing at both sea and land targets, and also built Mayville town north of the canal for the workers.

After the Armistice following World War I, a huge hutted camp was established at Harfleur as a basis for dealing with the transit of thousands of troops being demobilised.

The British soldier Arthur Bullock recorded in his memoir what life was like there, together with a humorous illustration of his Nissen hut, labelled 'Home Sweet Home'.