St-Denis was founded in 1668 by the first governor Étienne Regnault, who named the settlement after a ship that ran aground here. But St-Denis didn't really start to develop until the governor Mahé de Labourdonnais moved the capital here from St-Paul in 1738; the harbour was in general more sheltered and easier to defend, and water more abundant.
The 19th century ushered in St-Denis' golden age. As money poured in from the sugar plantations, the town's worthies built themselves fine mansions, some of which can still be seen along Rue de Paris and in the surrounding streets. But in the late 1800s the bottom dropped out of the sugar market and the good times came to a stuttering end. St-Denis' fortunes only began to revive when it became the new departmental capital in 1946. To cope with the influx of civil servants, financiers and office workers, the city expanded rapidly eastwards along the coast and up the mountains behind. Even today the cranes are much in evidence as St-Denis struggles to house its ever-growing population.