The Rhône Valley is located between two mountain ranges, the Massif Central and the Alps. The Massif Central was once as high as the Himalayas but is so ancient (formed 600 million years ago) that it is continually collapsing and now forms gently rolling hills. The Alps are younger and therefore taller.
The Northern Rhône is known for its steep slopes and narrow terraces. The climate is continental (while the Southern Rhône is Mediterranean) with cold winters and hot summers. The famed Mistral wind helps cool the grapes during these hot summers, and keep the vines dry. The only red grape permitted in the Northern Rhône is Syrah, while the white grapes include Viognier, Roussanne, and Marsanne.
The Hermitage appellation is a single 650 ft hill above the Rhône River. Part of the Massif Central, the Hermitage hill has a diversity of soil types. Four geological eras merge at this one point (granite from the primary era, fragments of limestone from the secondary era, hills from the tertiary era, and glaciations from the ice ages), creating the varied and complex terroir that has made Hermitage an iconic appellation.