Unterschächen is a municipality in the Canton of Uri in Switzerland , situated in the upper Schächental .

Unterschächen has an area, as of 2006, of 80.3 km2 (31.0 sq mi). Of this area, 35.6% is used for agricultural purposes, while 9.4% is forested. Of the rest of the land, 0.8% is settled (buildings or roads) and the remainder (54.2%) is non-productive (rivers, glaciers or mountains). In the 1997 land survey, 5.6% of the total land area was heavily forested, while 2.1% is covered in small trees and shrubbery. Of the agricultural land, 4.3% is used for orchards or vine crops and 31.3% is used for alpine pastures.