The small museum on the island covers the history of Saint-Louis from its founding as a French trading post through to Senegalese independence. The collection includes colonial-era maps, photographs, and artefacts that give useful context before you walk the streets. The building itself — a restored colonial house — is part of the attraction. Opening hours can be erratic; mornings are your best bet.
Musée du Delta
Colonial-era history museum in a restored island house