Indeed, it is.
http://seethesouthwest.com/2402/valles-caldera-new-mexicos-supervolcano/
Actually, many inland areas have volcanos in this country ~ there are two under Lake Superior ~ and there's definitely a serious hotspot (denoting some really old volcanos) in Southern Indiana, and under the Appalachians.
Death Valley has more than its fair share of volcanic vents ~ and up until recently folks hadn't even noticed those volcanoes.
Much of our continental crust is crisscrossed with failed rifts, and really ancient volcanos covered over with thousands of feet of shale and disaggregated schist. What is most disturbing with this structure is that it was recently discovered that if the upper mantle decides to surge upward it can MELT those ancient volcanic plugs and come right on up to the surface!