Canal d'Ille-et-Rance, Summit level canal in Brittany, France.

The Canal d'Ille-et-Rance is a summit level waterway running roughly 79 kilometers through Brittany and connecting Dinan to Rennes. The system includes 47 locks and maintains its water level at around 65 meters elevation, with a 7-kilometer section linking the Atlantic to the English Channel.

Work began at Hédé on 12 June 1804 under Napoleon, then stalled after his defeat; a private company resumed in 1822 and the canal opened in 1834. The Hédé lock flight took nine years and was handed over in October 1817, when the Duke of Angoulême visited the site. Ownership passed from the State to the Brittany Region in 2010.

The canal takes its name from the rivers Ille and Rance, and in Breton it is Kanol an Il hag ar Renk. Its most concentrated feature is the ladder of eleven locks packed into 2.2 km near Hédé, where boats are raised across the summit at Bazouges-sous-Hédé. Hire firms are based on the canal and its connecting waterways, so the waterway is used today by cruising boats rather than freight.

The canal runs 84.8 km from the Mail lock at Rennes to the Châtelier lock at Saint-Samson-sur-Rance, with a 7 km summit level at 65 m where drought can restrict lock use. Between Montreuil-sur-Ille and Évran, eleven locks follow one another within 2.2 km at the Bazouges-sous-Hédé watershed. The Rance estuary route to Saint-Malo passes the Rance tidal power station barrage.

The 2.2 km between Montreuil-sur-Ille and Évran packs eleven locks in quick succession as the canal climbs over the Bazouges-sous-Hédé watershed. The Hédé lock staircase alone took nine years to build and was handed over in October 1817, in time for the Duke of Angoulême to inspect it.