The Saint-Louis region (French: Région de Saint-Louis) of Senegal is on the border with Mauritania. Its capital is Saint-Louis.

Famous for the cast iron bridge in its capital, built by French colonialists in the 19th century, the region includes the Djoudj National Bird Sanctuary, home to thousands of birds, some indigenous to the area.

Saint-Louis region is divided into 3 départements:

• Dagana département
• Podor département
• Saint-Louis département

Saint-Louis is traversed by the northwesterly line of equal latitude and longitude.

• Lac de Guiers