Samnaun (Romansh: Samignun) is a high Alpine village and a valley at the eastern end of Switzerland and a municipality in the Engiadina Bassa/Val Müstair Region in the Swiss canton of the Grisons .

The valley was first used as a seasonal mountain pasture for the villages of Tschlin and Ramosch . By 1220 the first permanent farm houses are mentioned. These farm houses and fields were given as a gift to the Marienberg Abbey by the counts of Tarasp in the 12th century.

As of 2006 Samnaun has an area of 56.2 km2 (21.7 sq mi). Of this area, 46.1% is used for agricultural purposes, while 11.7% is forested.