The lake was formed approximately 19,000 years ago by the retreat of the Würm glaciation ice tongue.
It contains the highest diversity of fish species among all lakes in France.
Hautecombe Abbey, located on the western shore, serves as the traditional burial place for the House of Savoy.
The lake's water level is artificially regulated by the CNR to manage flow into the Rhône.
The depth of the lake results in a high thermal inertia, keeping water temperatures milder than shallower regional lakes during autumn.
It has been protected under the international Ramsar Convention since 2003 due to its critical wetland status.
The underwater landscape features steep slopes that plummet rapidly from the shoreline to the lake bed.
Lac du Bourget is France's largest and deepest natural lake located entirely within national borders. It is a glacial-origin lake situated in the Savoy region, flanked by the Jura Mountains to the west and the Bauges massif to the east. The city of Aix-les-Bains occupies its eastern shore, serving as a historic spa town since the Roman era. The lake reaches a maximum depth of 145 meters and stretches approximately 18 kilometers in length. It acts as a major ecological corridor and is home to the Hautecombe Abbey on its rugged western bank. The water body is fed primarily by the Leysse River and drains into the Rhône via the Savières Canal. It is a Ramsar-designated site recognized for its significant freshwater wetlands and bird habitats.
The Belvédère du Revard provides a panoramic view of the entire lake and the surrounding mountain ranges.
Rent a bicycle to use the dedicated path connecting Aix-les-Bains to the wilder northern tip of the lake.
Check wind forecasts before kayaking, as the thermal winds from the mountains can create choppy surface conditions by mid-afternoon.
Visit the public beaches in Aix-les-Bains for designated swimming areas with lifeguard supervision during the summer.
Do not attempt to swim or boat in the wild western sections without knowledge of the local currents and sudden depth changes.
Boat tours and commercial water-sport rentals operate primarily from spring through early autumn.
Respect protected natural zones along the shoreline; remove all litter and refrain from feeding waterfowl to protect the ecosystem.
