The Cahokia Mounds (also simply known as Cahokia) (11 MS 2) is the site of a Native American city (which existed c. 1050–1350 AD) directly across the Mississippi River from present-day St. Louis. The state archaeology park lies in south-western Illinois between East St. Louis and Collinsville. The park covers 2,200 acres (890 ha), or about 3.5 square miles (9 km), and contains about 80 manmade mounds, but the ancient city was much larger.
A river city reaches its peak
In the years around 1050 CE, the city-proper's three urban precincts: St. Louis, East St. Louis, and Cahokia were constructed. At the same time, an ordered city grid—oriented to the north along the Grand Plaza, Rattlesnake Causeway, and dozens of mounds—was imposed on earlier Woodland settlements. This was accompanied by a homogenization of material culture (e.g. pottery and architectural styles) that divided the smaller settlements beforehand. Mound construction increased across the region in the 11th century in the floodplain and, for the first time, in the uplands to the east.
Some mounds were built on earlier settlement locations—arguably by descendants emphasizing their particular ancestral positions in the new social order. In the centuries preceding 1000 CE, American Bottom populations were living in small settlements of 50 to 100 people that were used for short durations of 5–10 years. At least two of these larger clusters were present at Cahokia, one dating to the mid-7th and 9th centuries. Later in time, many began to be constructed along cosmologically organizing principles, emphasizing cardinal directions and distinct sectors of society.
By the end of the 10th century, many of these settlements aggregated into larger groups. These larger villages included the earlier cosmogram layouts complete with large central posts, pits, and/or structures. An extensive nucleated community sprawled across 35–70 hectares (86–173 acres) in Cahokia proper, with its beginnings at the end in the late 900s CE.
Farming and urban life
Cahokia was surrounded by rich agricultural lands. The city has been traditionally thought to have been a maize-centric civilization, the crop having been introduced to the region around AD 900. While maize is often credited with enabling Cahokia's early population growth, more recent research has suggested that Cahokian diets were quite varied, especially in the city's early period of existence. A diversity of crops, such as goosefoot and sumpweed from the Eastern Agricultural Complex, were grown and eaten at Cahokia.
Cahokian residential zones were arranged into carefully planned clusters around plazas and mounds. Specific delineations and functions have been hard to determine, but many of these clusters may have been designed to accommodate religious or ethnic segregations. Cahokia's neighborhoods possessed a standardized suite of building types, including steam baths, council houses, and temples. Cahokian domestic structures were generally of pole-and-thatch construction and followed rectangular footprints. Wall trenches were often used instead of posts for building construction. Early in its history, Cahokia underwent a massive construction boom.
Along with the early phase of Monks Mound, an overarching urban layout was established at the site. It was built with a symbolic quadripartite worldview and oriented toward the four cardinal directions with the main east–west and north–south axes defined with Monks Mound near its center point. Four large plazas were established to the east, west, north, and south of Monks Mound.
Earthworks and observation
Monks Mound is the largest structure and central focus of the city: a massive platform mound with four terraces, 10 stories tall, it is the largest man-made earthen mound north of Mexico. Facing south, it is 100 ft (30 m) high, 951 ft (290 m) long, 836 ft (255 m) wide and covers 13.8 acres (5.6 ha). It contains about 814,000 yd (622,000 m) of earth. The mound was built higher and wider over the course of several centuries, through as many as 10 separate construction episodes, as the mound was built taller and the terraces and apron were added.
The Cahokia Woodhenge was a series of large timber circles located roughly 850 m (2,790 ft) to the west of Monks Mound. They are thought to have been constructed between 900 and 1100 CE, with each one being larger and having 12 more posts than its predecessor. The site was discovered during salvage archaeology undertaken by Dr. Warren Wittry in the early 1960s interstate highway construction boom. Although the majority of the site contained village house features, a number of unusually shaped, large post holes were also discovered.
During excavation of Mound 72, a ridge-top burial mound south of main urban precinct, archaeologists found the remains of about 270 individuals, including paired male/female burials. One burial (Feature 101) was buried on a bed of 10,000 marine-shell disc beads arranged in the shape of a falcon, with the bird's head appearing beneath and beside the man's head, and its wings and tail beneath his arms and legs.