High Plains—Introduction

drawing of outline of this region on Kansas map

High Plains--Intro | High Plains--Rocks and Minerals
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Download fact sheet on the rocks and minerals of the High Plains.

In Kansas, the High Plains region comprises almost all of the western one-third of the state. It is an area of vast flatlands and gently rolling hills, with topographic relief largely restricted to streams and river valleys, such as the Arikaree Breaks in Cheyenne County or along the Cimarron River in Seward County.

color photo of flat landscape, with cornfield in foreground and stone farmhouse on horizon

Typical High Plains flatlands, Phillips County.

The High Plains developed on sediments that originated in the Rocky Mountains to the west. The Rocky Mountains were formed by deformations of the earth's crust at intervals during the last part of the Cretaceous Period and continuing into the Tertiary Period, which lasted from approximately 66 million to 1.6 million years ago. By late Tertiary time, just a few million years ago, the Rockies were being eroded by wind and water. Streams flowing eastward out of the Rocky Mountains were full of sand, gravel, silt, and other rock debris. Over millions of years, this mass of eroded material filled the stream valleys and eventually covered the hills, creating a huge, gently sloping floodplain. The remnants of that region (which extends far beyond the Kansas border) is the region we call the High Plains.

The great wedge of sand and gravel that lies below the surface is the Ogallala Formation. The Ogallala is made up of the unconsolidated deposits (sands, gravels, clays, and other materials) that eroded off the face of the Rockies. Some of this material was cemented together to form porous sandstones, which are known as mortar beds. Most of the Ogallala is underground, but it crops out in many places, such as at Scott County State Lake. The Ogallala is one of the chief sources of ground water in western Kansas.

color photo of porous sandstone, reminiscent of elephant in profile

Elephant Rock in northwestern Decatur County is an eroded outcrop of the Ogallala Formation.

The High Plains get less precipitation than other parts of the state, averaging between 15 and 25 inches a year. The combination of low precipitation, windiness, and abundant sunshine makes for a dry, or semiarid, climate in much of the High Plains. Short, drought-tolerant grasses cover the uncultivated areas, trees are scarce, and desert-type plants, such as cactus and yucca, are common.

Text by Liz Brosius, Kansas Geological Survey. Unless noted otherwise, illustrations by Jennifer Sims, Kansas Geological Survey; photographs by John Charlton, Kansas Geological Survey.

High Plains--Intro | High Plains--Rocks and Minerals
High Plains--Places to Visit | Other regions