Driving west through Kansas on Interstate 70, one enters the Flint Hills west of Topeka. The highway undulates across this uplifted plateau of Permian sediments, which has been carved into a series of parallel ridges and valleys by stream erosion. At Junction City, the traveler leaves the Flint Hills and, in order, crosses the valleys of the Smoky Hill, Solomon and Saline Rivers; the latter two streams are tributaries of the Smoky Hill River but all three flow eastward across western Kansas.
West of Salina, one begins to sense a steady climb toward the High Plains. The Interstate ascends a series of low escarpments and, to either side of its route, the traveler notes cones, domes and truncated ridges that are erosional remnants of once higher terrain; though the highway dips along the way, the climbs are greater than the descents and the road's elevation gradually increases. At Salina, the elevation is about 1200 feet, at Russell it is above 1800 feet, at Hays it exceeds 2000 feet and at Wakeeney it is 2450 feet. The staircase topography is most evident between Salina and a broad ridge across Lincoln and Ellsworth Counties, which harbors the vast Smoky Hills Wind Farm; beyond that ridge, the terrain begins to flatten out and becomes especially featureless on the High Plains of western Kansas and eastern Colorado, where a veneer of Tertiary sediments lie atop the Cretaceous strata of the Great Plains.
The traveler will also note that the landscape becomes gradually drier west of Salina as one proceeds farther from the plumes of Gulf moisture that invade the Heartland and closer to the rain shadow of the Rocky Mountains. Trees, relatively abundant in Salina, become less widespread as one continues westward; by the time the traveler reaches the High Plains, trees are restricted to stream beds and irrigated homesteads.