The Swannanoa Gap Letterbox

In Western North Carolina take Exit 66 , Interstate 40. Go north to the
stop sign. Take a right turn and go 0.9 mile to another stop sign. Go
left on the road less travelled about 0.9 mile to the gate. Do not let
your private thoughts impede your progress as you imagine the triumph of
nature in its slow reclimation of man's old road through the forest. 579
paces down the road, where the rock face on the left comes closest to
the road two young poplar grow. And there under flat stones rests that
which you seek.