What is "tombelaine"

Tombelaine is a small tidal island off the coast of Normandy in France. It lies a few kilometres north of Mont Saint-Michel. At low tide the island can be reached on foot (with a guide) from the coast of Cotentin, to the northeast, and from Mont Saint-Michel.

The island lies just to the south of the course of the Sélune river, which has to be forded to access the island from Cotentin. The island is by , and high. It is composed of granite. It is in the commune of Genêts.