The World Heritage site lies on the borders of the cantons of St. Gallen, Glarus and Graubünden, extending over an area of more than 300 km2 (124 square miles), across 13 communes. The lowest-lying point is at Ennenda (just under 520 m above sea level) and the highest elevation is Ringelspitz (3247 m a.s.l.).

The boundary is primarily marked by topographical features such as waterbodies, valleys, ridges, forest edges or roadways. It often coincides exactly with the boundaries of existing protected areas.