An earth lodge is a distinctive type of timber-frame house built from the early 1400s to the late 1800s by a dozen different Plains Indian tribes. These massive circular structures, often encompassing 1,500 square feet or more, featured four large support posts arranged around a central fireplace. The walls were formed by a ring of shorter posts and rafters were laid between the center posts and the wall posts. The resulting wooden shell or framework was then covered with successive layers of willow branches, a matting of prairie grass, and finally sod or earth. The entryway consisted of a projecting passage six to fifteen feet in length.
The Upper Republican culture, which occupied northeast Colorado, western Nebraska, northern Kansas, and southeast Wyoming from 1100 to 1300 built early versions of these dwellings. However, the best-known earth lodges were built in the 1700s and 1800s by the Mandans, Hidatsas, and Arikaras, all of whom were bison-hunting farmers living on the Missouri River. The first detailed description of an earth lodge was written in 1804 by Patrick Gass, a member of the Lewis and Clark Expedition. In the early 1830s, well-known artist Karl Bodmer made detailed drawings of Mandan earth lodges, including an interior scene that shows how it was used.
Classic earth lodges such as those built by the Missouri River farmers have not been discovered in Colorado. However, cultural groups of the Central Plains Tradition, including the Upper Republican culture, built timber-frame houses that most archaeologists regard as precursors to historic-era earth lodges. While Central Plains lodges have not yet been documented in Colorado, Upper Republic groups regularly visited the state and may have lived in the South Platte River Valley for extended periods of time. The Buick Campsite, located near present-day Limon, features a temporary structure built by Upper Republican people. The Buick site, along with others such as the Donovan site located in northern Logan County, demonstrate repeated seasonal Upper Republican use of Colorado’s High Plains landscape.
Like classic Mandan, Hidatsa, and Arikara earth lodges, Central Plains Tradition culture lodges featured four central support posts around a central fire place as well as an extended entryway. The walls of Central Plains lodges were made from clay, known as daub, plastered over a framework of small branches covered with grass. The roofs were also made from branches, grass, and daub. However, in contrast to historic-era earth lodges, Central Plains lodges were square or rectangular in plan, and most were about half as large.
Classic earth lodges and Central Plains Tradition culture lodges share a number of similarities with the pithouses built by Ancestral Puebloans who lived in southwest Colorado. Like the Plains houses, Puebloan pithouses of the Basketmaker II and Basketmaker III periods were earth- or daub-covered timber-frame buildings. However, Puebloan houses were built in pits that were two to three feet deep, while earth lodges were mostly built on the surface or in shallow pits no more than one foot deep. Many lodges of the Central Plains tradition were built on the surface, although some were built in pits up to four feet deep. Some Puebloan pithouses also incorporated vertical rock slab foundations, which were not used in the construction of Plains houses.
The people who built the classic earth lodges, as well as earlier Central Plains tradition culture lodges, were farmers who also hunted bison and other animals. Because they grew corn (maize), beans, squash, sunflowers, and other crops, their houses were built close to river and stream floodplains, where cultivation was easier and groundwater was more abundant than on the nearby upland prairies. Because they lived in one location for most of the year, their lodges contained numerous underground storage pits, where they kept surplus food, tools, and other items.
The cosmological principles and cultural values embodied in earth lodge architecture remain important to native peoples today. Earth lodges continue to be built on the Fort Berthold Reservation (Mandan, Hidatsa, and Arikara Nation) in western North Dakota. In addition, the National Park Service built a replica earth lodge at the Knife River Indian Villages National Historic Site near Stanton, North Dakota, and several replica lodges are located at Fort Abraham Lincoln State Park south of Mandan, North Dakota. The Dancing Leaf Earthlodge, a replica Central Plains tradition house, is located in Wellfleet, Nebraska, twenty miles south of North Platte.