The US government keeps a record of 16,525 places that no longer exist. What a vanished town actually leaves in the ground, and why the dot on the map is only ever a starting point.
The protected core of a battlefield is closed to you. The mapped study area around it is often private farmland — and the camps out there beat the firing line.
44,677 abandoned metal mines are on record. The camp is never quite where the mine is; cabin platforms, dumps and haul roads are how you find the difference.
Oregon, California, Mormon Pioneer, Pony Express, Santa Fe and Old Spanish — what survives of them, how ruts and swales read in elevation data, and why the stopping places matter more than the route.
Where to get old maps free, what the symbols mean, and how to line a century-old sheet up with the ground you are standing on.
Hillshade, slope, Local Relief Model, and sky-view openness — what each one is actually showing you, and when to reach for which.
What a vanished foundation, root cellar, or filled-in farm road actually looks like in elevation data, and how to narrow down where to search before you go.
Private land, public land, and protected sites are three very different situations. General ground rules — not a substitute for checking the specific site.