Which preposition to use with signpost

of Occurrences 4%

Signposts of adventure.

in Occurrences 3%

Surely, my lords, men of this unbounded benevolence, and this exalted genius, deserve such honours as were never paid before; they deserve to bestride a butt upon every signpost in the metropolis, or to have their countenances exhibited as tokens where this liquor is to be sold by the license which they have procured.

to Occurrences 3%

Michael Angelo and his editors supply no arguments or mottoes for his poems; while those printed by Adami in his edition of Campanella are, like mine, meant obviously to serve as signposts to the student.

at Occurrences 2%

At the end of these two miles the valley itself branched into two and climbed inland, the road branching likewise; and M. Benest's mark was the signpost at the angle.

Which preposition to use with  signpost