In the book "Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers" it says:
The octothorp ("8 fields" ) has been used in cartography as a symbol for "village "... .
But, the octothorp, as a number sign, is used in the U.S. to signal an apartment or unit within the block at a particular address. For example:
Mr. M Murphey
72 President St #4
Is it possible that this use of the octothorp has its roots in its use in older cartography to mark the site of a village?