Gorges du Sierroz, Natural canyon in Grésy-sur-Aix, France.

The Sierroz Gorges is a canyon carved by the Sierroz river between Mont Revard and Lake Bourget. The rocky walls rise up to 20 meters high and stretch for about 800 meters along the river course.

Mills, a press and sawmills already used the Sierroz here before tourism developed. In 1813 Baroness Adèle de Broc drowned in the gorge before her friend Queen Hortense de Beauharnais. After Savoy joined France in 1860, Napoleon III and Empress Eugénie visited on 29 August 1860. A dam was built in the 1880s and boat trips ran from 1881 until 1971; the gorge became Savoie's first classified natural site in 1910, closed in 1980 and reopened in July 2021.

The gorges appear in works by Alexandre Dumas, Alphonse de Lamartine and Pierre Benoit, and in Shepherd Knapp's wartime account. Raphaël Massard composed a piano waltz, Gorges du Sierroz, in 1897, dedicated to Mademoiselle Collomb; Pascal Gallet recorded it for the first time in 2024, and an orchestral version dates from 1898.

A well-maintained path runs along the canyon with parking available at the entrance. Two bridges anchored to the rock walls allow visitors to cross the river and explore different viewpoints.

The gorges hold the only known Savoy location of the tuberous comfrey, recorded in the ZNIEFF type I inventory since 2007. At just 350 m altitude, the shaded, enclosed valley lets mountain species such as the beech, the silver fir and the spiked chervil grow at low elevation, a so-called abyssal station.