What it is
A town founded by French traders in 1659 on a narrow island in the river, linked to the mainland by the Faidherbe bridge and to a sandspit, the Langue de Barbarie, on the ocean side. It was the capital of French West Africa until 1902 and of Senegal until 1957. UNESCO listed the island in 2000.
Why go
The grid of colonial buildings with wooden balconies is intact enough to walk for an afternoon, and much of it is decaying in plain sight rather than restored. The fishing quarter at Guet Ndar on the spit is one of the densest working fishing settlements on the coast. Djoudj National Bird Sanctuary, about 60 km north near the Mauritanian border, holds pelicans, flamingos and very large numbers of European migrants through the northern winter. Saint-Louis also hosts a long-running jazz festival.
When to go
November to March for the birds at Djoudj, which is the main reason to come this far north; the sanctuary is at its fullest between December and February. The town itself is fine year-round, though April to June is hot. Coastal erosion on the Langue de Barbarie is severe and ongoing, and some of what guidebooks describe there has gone.
Most people stay 2 nights.