A round 1855 the epidemic of Oregon fever began to die down, as more and more settlers discovered that they did not need to go so far west to find fertile, uncrowded land.

For many years the Great Plains had been considered a vast wasteland—the Great American Desert, some called it. Explorer Stephen H. Long pronounced it "unfit for cultivation and, of course, uninhabitable by a people depending upon agriculture for their subsistence."

But the overlanders had found that this was not an accurate picture of the plains. Instead, Addison Crane noted, "Every acre as far as the eye could see was clothed with verdure [green vegetation], and the soil is as the best of Indiana."

As reports like these made their way east, more and more discontented farmers thought of relocating to the Great Plains. The influx of...