Previously called "l'Eguillon", meaning "the sharp point", l'Aiguillon gave its name to both the bay and the town. The bay of l'Aiguillon stretches 20km over a near perfect arc. It is most often used by 'boucholeurs' (mussel farmers) who positioned thousands of stakes along the borders of the estuary. These stakes are used to breed mussels.

L'Aiguillon sur Mer was originally an island with the "Grande Rade" (a large natural harbour) to the east, the sea to the south, the Grand Lay river to the west and the Chenal de la Raque to the north (the channel which linked the Lay to the 'rade' area). Soon the island once again became part of the mainland as the channel to the north-west filled with drifting sand and silt brought in by high tides.

The dunes on which l'Aiguillon is built were created between the 5th and the 12th centuries. During the 18th century the sea submerged a large part of the town, reaching up to 2 km inland from la Pointe de l'Aiguillon and over an area I km wide. The old town having disappeared under the sea, its inhabitants sought refuge further inland and settled where the town is now.

As there are no cliffs, the coastline has very little defense against the sea. The land to the south of the town is nowadays protected by a 5 km long seawall built in the 19th century.

L'Aiguillon sur Mer epitomises the whole of southern Vendée and our Côte de Lumière.

The history of the area around Aiguillon is unusual. Ancient inhabitants of the Poitou area were called Pictons. Before the year 1000 the present coastline was very different and a vast gulf stretched from the south of Talmont, to Luçon and Fontenay-le-Comte. Many islands rose from the waters of the "Sinus pictonum".

The island of Condate (Saint-Michel-en-l'Herm) became one of the 'high places' when in 682 the Bishop of Poitiers, Ansoald, had an abbey built there. During the Carolingian era, Vikings landed at the mouth of the river Lay, conquered the powerful monastery and spread throughout the region leaving desolation in their path.

During the 12th century, Benedictine monks started to drain the marshes with fellow members of abbeys at Nieul-sur-l'Autise, Maillezais, l'Absie and Saint-Maixent. "Le Canal des Cinq Abbés" (The Canal of the Five Abbots) is a reminder that the leaders of the five monasteries turned these marshy lands into a more prosperous region.

The Bay of l'Aiguillon is what remains of the famous ancient gulf where four canals and the River Sevre-Niortaise joined by pure waters of the River Vendée all merge. The River Lay flows into the sea between a long dyke and a stretch of land called "La Pointe d'Arcay".

The most recent reclaimed land in the Gulf lies to the west of the Digue du Génie built for that purpose during the first half of the 20th Century.