[LewisNClark]

Happens all over. Many times a historical site is on private property...and state, local, and fed. governments don't want tourists invading private property owner's property (many times in farm fields). Too bad the sites were not protected, but too late. The famous L & C Fort Mandan in North Dakota is 14 miles away (in middle of a wheat field) from where the replica fort is located and the local museum visitors' center in Washburn, ND tell their staff not to give directions to the actual site.

Sometimes actual sites are simply off the beaten path that tourists would never pass, so they put the signs on roads where they will most frequently be seen.