Articles in this series are exploring changes in American politics, culture and technology, drawing on the reporting and personal experiences of New York Times journalists around the country.

Along a curve of mountain road in far northern Idaho, there’s a dinged and rusted guardrail above the tiny town of Sandpoint. The rail is a bit of practicality on a two-lane stretch with hairpin turns; its dings attest to the lives, or vehicles, saved by blocking the way.

But stand there for a while, turning your gaze in any direction at a landscape mostly empty of human imprint, and it’s easy to see that little ribbon of highway metal as a perimeter fence. Sandpoint huddles at the bottom, its 7,500 people squeezed together in a tight embrace. The West, writ large, splays out sky and earth in every other direction.

In some ways, it’s the perfect place to see hard Western reality — the geographic and economic isolation that has crushed countless hamlets like this one, including new ghost towns in the making from Oshkosh, Neb., to Pedro Bay, Alaska.