AtD translation: posted trail

[Mike Jing]

P598.29-37   “But you are being used by your racial memory here,” declared
Humfried indignantly, “you are out looking for some Hun.”
       “Are you saying I want to be overrun and conquered, Humfried?”
       “Did I say that?”
       “Well . . . suppose I do, is that, one, any business of either of
you, two, anything I feel that I must apologize for, two point one—”
       “Yash, you are flat correct,” Kit nodded, “we’re all just
night-riders here miles up a posted trail, making pests of ourselves. Ought
to be shot, well, shot at, anyway.”

What is a "posted trail" exactly?