Kincaid Mounds Earth Cache EarthCache

The Kincaid Mounds Illinois Historic Site consists of 105 acres at the heart of the Kincaid Mounds Archaeological Site. Portions of the Archaeological Site extend to private property north and east of the Historic Site. The State property has been designated a National Historic Landmark and is on the National Register of Historic Places of the United States. At present, public access is limited to an observation/interpretation platform adjacent to Kincaid Mounds Road.

To visit Kincaid Mounds, take the Unionville Road east from Route 45 at the north edge of Brookport. Go 6.25 miles (through Unionville) to the New Cut Road, then south on New Cut Road for 3.6 miles to the Kincaid Mounds Road. Drive east for .6 of a mile to the observation and interpretation platform (see location map).  The interpretive platform area is open from dawn to dusk.

A. To meet the educational objective of the earthcache, send the answers to my email by selecting the link above. Please do not include the answer in your posted log.

1) What two geophysical methods were used to survey the Kincaid site by archeologists?

2) Name the type of soil and its source that was used to build the mounds and support the crops at the Kincaid site?

3) According to the link below, what is unique about Pope County Mound #2?

After leaving the observation area, one can proceed east along the road. You will soon enter the woods at the Pope County line. Keep looking on the left side of the road for additional privately owned mounds in the wooded area. The last notable mound has the remains of an old house on it. At this point turn around and retrace your route back west or continue on to the town of New Liberty where you can continue on to Golconda or return to Brookport.

Floodplains are landscapes shaped by running water. As streams and their larger forms, rivers, flow across the surface of land, they transport eroded rock and other material. (Erosion is the gradual wearing away of Earth surfaces through the action of wind and water.) At points along that journey, when their flow slows, the material they carry is dropped to create what are termed depositional landforms. Among these landforms are deltas and floodplains.   A floodplain (sometimes spelled flood plain) is an area of nearly flat land bordering a stream or river that is naturally subject to periodic flooding, but are otherwise normally dry for most of the year. A flood occurs when the flow of water in a stream becomes too high to be accommodated in the normal stream channel.  In a flood, water flows over the stream's banks, submerging the adjacent land. Depending on the amount of water, the flood may cover all or part of the floodplain. As water flows out of the stream's channel, it immediately slows down. The material carried by the river—sediment such as gravel, sand, silt, and clay—is deposited on the floodplain.  The general term for sediment deposited by running water is alluvium (pronounced ah-LOO-vee-em). Because floodplains are covered with alluvium, they are often called alluvial plains.


Silt and clay deposited on a floodplain make the soil there extremely fertile. Floodplains can support particularly rich ecosystems, both in quantity and diversity. They are a category of riparian zones or systems. A floodplain can contain 100 or even 1000 times as many species as a river. Wetting of the floodplain soil releases an immediate surge of nutrients: those left over from the last flood, and those that result from the rapid decomposition of organic matter that has accumulated since then. Microscopic organisms thrive and larger species enter a rapid breeding cycle. Opportunistic feeders (particularly birds) move in to take advantage.As a result, a floodplain is rich agricultural land. The disadvantage of farming on a floodplain is the natural hazard of floods.  


Kincaid Mounds is located at the northern boundary of the Black Bottomalluvial plain of the Ohio River.  Black Bottom is located between Brookport, Illinois and Evansville, Indiana.  According to radiocarbon dates of organic matter, the flood plain reached its current outline 1000 years ago or earlier.   This bottom reaches a maximum of 5 km in width and is characterized by a ridge-and-swale topography. This type of topography is very fertile and free of flooding compare to other floodplains, making the Black Bottom an ideal site for settlements.  It has been estimated that the fertility of the Black Bottom floodplain supported as many as 1,500 people during the Mississippian period.

The arrival of corn and intensive corn cultivation in the eastern United States over 1000 years ago transformed the dominant native American groups there from mobile hunters, gatherers, and gardeners able to support only small villages to sedentary farmers able to support larger towns and even small cities. This transformation gave rise to the people or culture we call "Mississippian" about 900 AD. This stable and abundant supply of food provided the Mississippian people more time to build of communal facilities such as platform mounds, defensive walls or stockades, and temples.  A complex chiefdom developed in which a male chief and his family exerted civil control over the community and priests who held religious authority over them.

Around 1050 AD, Mississippian leaders and their followers arrived in what is now eastern Massac and southern Pope Counties of Illinois and established scattered farming villages and a cultural center at what we call Kincaid Mounds today, named after early European owners of the site. The region they selected was a wide section of the floodplain of the Ohio River near the mouths of the Tennessee and Cumberland Rivers now known as the Black Bottom. It was a forested area with rich alluvial soils whose fertility was replenished by almost annual overflow by the Ohio. Without this fertile floodplain they would not have been able to grow their primary crops of corn, squash and several oily and starchy seed bearing plants (sunflower, marshelder, lambs quarter, may grass, knotweed, little barley). The specific site was a high ridge bordering the north side of Avery Lake and about a mile north of the present day Ohio River. Its high elevation reduced the frequency of flooding and made it suitable for a ceremonial and administrative center.

Kincaid was a near neighbor of Cahokia, only 140 miles (230 km) away, and is thought to have been influenced by developments there. The Kincaid site likely served as a trade link between native settlements in the Cumberland-Tennessee river valleys and the metropolis at Cahokia.

The average temperature of the climate at the time of the founding of Kincaid was about 5 degrees warmer than today. This was during what climatologists call the "Medieval Warm Period" which lasted from AD 800 to AD 1200. Climate cooling after this time, culminated in what climatologists call the “Little Ice Age” about AD 1350 when temperatures were colder than today. This colder climate may have played a role in eventual abandonment of Kincaid about AD 1400.

By the year 1500, the area including Kincaid, Cahokia, and the lower reaches of the Tennessee and Cumberland Rivers was empty of all significant cultural complexes. This region at this time is called the "vacant quarter" by archaeologists. Where the Kincaid people went is not known, but the shift to a colder climate, depletion of timber for fuel and construction materials, and the decline of central control may have all played a role. At any rate the Indians that had moved back into the area by the time of European arrival in the late 18th century had no idea who made the mounds.

The site was the subject of major excavations by the University of Chicago from 1934-1941, during which a number of famous anthropologists and archaeologists were trained under the direction of Fay-Cooper Cole. These included Richard MacNeish, discoverer of the origins of maize. Scientists from Southern Illinois University at Carbondale did salvage excavations in the late 1960s when the Massac County portion of the banks above Avery Lake were leveled by a farmer to create a small crop field. They also excavated several small Mississippian farming villages near Kinacid.

The Chicago excavators in the 1930s documented a prehistory in the Kincaid area stretching back thousands of years, into what is now known as the Archaic Period and was described as a pre-pottery culture otherwise very like the cultures of the Early Woodland, such as the Adena culture. More intensive occupation was documented in the ensuing Early Woodland and Middle Woodland periods. This involved a sedentary, semi-agricultural culture characterized by the use of limestone-tempered ceramics and the presence of permanent wooden houses. The Baumer culture was similar to the Adena culture and Hopewell culture, with which it was contemporary. The Baumer occupation at Kincaid was shown to be extensive. Occupation continued into the Late Woodland. This period is known as the Lewis culture. The recognizable occupation at Kincaid, however, is the Mississippian mound-building community that developed out of the local Lewis community about 1050 AD.

A geophysical survey with new technology and excavations by teams from Southern Illinois University since 2003 has yielded significant new data. of the state-owned land at Kincaid. The principal instrument for this work is a fluxgate gradiometer. This instrument measures minute variations in the strength of the local magnetic field which are caused by subsurface features such as hearths, pits, and burned houses. The survey suggested that the site is more extensive and more complex than had been previously understood. Most notably, the occupation appeared to extend much farther west than we had realized, with a western extension of the palisade enclosing this area.