The Willa Cather Foundation has a nice website and is currently in charge of a 600+ acre prairie reserve in central Nebraska which has never been broken by plow.
There are few places in the world that have not had to bend to the will of modern man, and they are all fascinating in their own way. In most cases, they are forbidding landscapes that have been left alone due to harsh extremes of topography and climate: wind-scoured mountaintops, searing deserts, and frozen polar expanses.
Here and there, by luck, whim or accident, prairies have been left alone too. These are not harsh landscapes. They do not beckon for intrepid adventure, but for quiet contemplation. We are lucky to have them as small vignettes to help us imagine what once existed on a much larger canvass.