The medieval city walls surrounding the city are well preserved.
Louis IX of France (Saint Louis) rebuilt the port in the 13th century as France's only Mediterranean port at that time. It was the embarkation point of the Seventh Crusade (1248) and the Eighth Crusade (1270). The town is actually several miles inland and the port, as such, would have been in nearby lagoons and estuaries, linked to Aigues-Mortes.
In 1893 a conflict between the French and the Italians who worked in the salt evaporation ponds of Peccais erupted, killing nine and injuring hundreds on the Italian side (Enzo Barnabà, Le sang des marais, Marseille, 1993).
The 1,650 metres of city walls were built in two phases: the first during the reign of Philippe III the Bold and the second during the reign of Philippe IV the Fair, who had the enclosure completed between 1289 and 1300. The Constance Tower, completed in 1248, is all that remains of the castle built in Louis IX's reign. It was almost certainly the gatehouse tower, designed to be impregnable with its six-metre-thick walls. A spiral staircase leads to the different levels of the tower.
From 1575 to 1622, Aigues-Mortes was one of the eight safe havens granted to the Protestants. The revocation of the Edict of Nantes in 1685 caused severe repression of Protestantism, which was marked in Languedoc and the Cévennes in the early 18th century by the "Camisard War". Like other towers in the town, from 1686 onwards the Constance Tower was used as a prison for the Huguenots who refused to convert to Roman Catholicism. In 1703, Abraham Mazel, leader of the Camisards, managed to escape with sixteen companions.
By road, Aigues-Mortes is about 35 km (21.75 mi) from Nîmes, préfecture (administrative capital) of the Gard département and 30 km (18.65 mi) from Montpellier, préfecture of the Hérault département. As the crow flies, Aigues-Mortes is 32.5 km (20.19 mi) from Nîmes and 26 km (16.16 mi) from Montpellier.
A rail branch line from Nîmes passes through Aigues-Mortes to its terminus on the coast at Grau-du-Roi. This line also transports sea salt.