Blue Highways had been a book about his wanderings along America's little-travelled byways, and while PrairyErth is similarly about the undiscovered heart of the United States, it focuses much more narrowly on a particular place.

[2] At the time that Least Heat-Moon was writing, there was political debate in Chase County about the possibility of a national park being created to preserve the prairie's ecosystems.

[4] A few years after the book was published, the Tallgrass Prairie National Preserve was created in a public-private partnership over 70,000 acres of Chase County.

[5]At the start of PrairyErth, Least Heat-Moon writes that if a traveler was driving US 50 from Maryland to San Francisco, the place where "she will exclaim from behind her windshield that she has at last arrived in the American West" is in "Kansas in the Flint Hills in Chase County".

It was there that the treelessness of the prairie would mean that the "world changes in a few miles from green to blue, from shadows to nearly unbroken sunlight, from intermittent breezes to a wind blowing steadily as if out of the lungs of the universe.

PrairyErth also discusses at length the county's ecology, geography, and geology, including a chapter on the ancient Nemaha Mountains, now deep below the surface.

"[2] Professor O. Alan Weltzien at the University of Montana Western has argued that Least Heat-Moon "like any essayist of place, advocates an essentially religious view of landscape: one that construes the land as divine, one whose expertise is marked by humility".