Set in the district of Aigle, the vast communal territory that constitutes the Ormont-Dessous makes it the fourth largest commune in the canton of Vaud. The Ormont-Dessous commune is home to six villages and hamlets : Le Sépey, Cergnat, La Forclaz, La Comballaz, Les Voëttes and Les Mosses.
Ormont-Dessous inhabitants are known as « Ormonans». The seat of the commune, which houses the communal administration centre and its schools headquarters, is the village of Le Sépey, located at 974m above sea level. The commune, which spreads far and wide over a surface area of 6367 hectares, boasts its highest point at the peak of Pic Chaussy with an altitude of 2351m.
The Ormont-Dessous commune's coat of arms, adopted in 1921, is symbolised by a tower representing the former Aigremont castle built in the 14th century, a mountain representing the Mont d'Or which is the central point of the commune and 4 stars symbolising the 4 « seytes » or sectors of the commune.
Today the commune lives primarily on its craft industry as well as on tourism and Ormont-Dessous counts the relatively small number of residents (200) of Les Mosses amongst its total 1'000 inhabitants.