The Green Mountains — a stop on Vermont Route 100.
The ridge running along your right is the Green Mountains, and this road threads the valley just east of the spine of them for its whole length.
They're old. Not Rockies-young, jagged and dramatic — these are the worn-down roots of a mountain range that was once Himalayan in scale, built when continents collided something like four hundred and fifty million years ago, and then ground down by half a billion years of weather and, most recently, by glaciers. What's left is rounded summits, deep notches, and a lot of exposed metamorphic rock — schist and gneiss and Vermont's famous marble and slate further south.
The Long Trail runs along that ridgeline — the oldest long-distance hiking trail in America, built between nineteen ten and nineteen thirty, running two hundred and seventy-odd miles from Massachusetts to Canada. It predates the Appalachian Trail and in fact inspired it; the AT shares its path for about a hundred miles in southern Vermont. Route One Hundred crosses it a few times, and you'll pass trailheads.
So on your right is a footpath older than most of the cars that have ever driven this road, running the whole length of the state through the woods.