About the Loess Hills

Unique Features of the Loess Hills
The Loess Hills have several unique characteristics.

In road cuts and other places where soil has been removed to expose a cross-section, the soil is typically uniformly loess. Only in the northern and southern ends of the Loess Hills is bedrock naturally exposed.

Loess is composed mainly of quartz silt, and is highly erosive. When exposed to water, loess will dissolve like sugar, hence the nickname "sugar clay" given to it by locals. Its composition also allows it to stand nearly vertical for long periods of time, as can be seen in road cuts throughout the region. Loess often sloughs on steep slopes, resulting in cat steps that are common throughout the hills.

National Significance of the Loess Hills Archaeology
The Loess Hills, known to scholars and laypeople alike as one of North America’s natural treasures, is also one of North America’s archaeological treasures. This unique landscape harbors hundreds of well-preserved earthlodge dwellings and palisaded villages built by the ancestral Plains Indians.

The archaeological legacy of the Loess Hills lies in the rich archaeological record that boasts of over 1,000 Late Prehistoric Glenwood earthlodges in the south and pairs of palisaded Mill Creek villages and ancient cornfields in the north. These two very differently expressed ancestral Plains Indian cultures occupied the Loess Hills at the same time and provide an unparalleled opportunity to explore 300 years of cultural diversity in this unique landscape. Transcending time, the archaeological legacy of the region is also tied to the struggle for Native Indian rights and events that would be instrumental in leading the nation toward protection and reburial of Native Indian remains. These characteristics are intrinsic to the archaeology of the Loess Hills and they are of unequivocal national significance.

Lewis and Clark Corps of Discovery
When Captains Meriwether Lewis and William Clark led their Corps of Discovery through this region in the summer of 1804, the Hills were covered with prairie. The scant trees that existed hugged the water ways. At that time, Oto and Missouri tribes lived in the southern part of the Hills and the Omaha in the mid-section of the Hills.

Change Comes to the Loess Hills
Around the 1850's, change came to the Loess Hills. Farms, communities and roads checked the wilderness that had cleansed the prairie of the always encroaching trees and woodland plants and, as you can see now, trees blanket most of the hills. Of the prairie that had covered the Hills, only 22,000 acres remain with about 4,500 acres being in the Broken Kettle Grasslands, the largest self-sustaining parcel of prairie in Iowa.

Now surrounded by forests and developed lands, the pockets of prairie in the Hills are islands of prairie flora and fauna not found until hundreds of miles to the west and not seen elsewhere in Iowa. Among these animals are the prairie rattlesnake (only in a very small area near Westfield in the northern Hills), plains pocket mouse, upland sandpiper, zebra swallowtail, ornate box turtle and plains spadefoot toad. Among the plants are ten-petal blazing star, spear grass, tumble grass and prairie moonwort. The native yucca is in the easternmost limit in North America.

Resources for Loess Hills Landowners

General Loess Hills Educational Resources and Websites:

Videos

Books and Academic Papers

Conservation and Recreation