Populations grow and permanent settlements increase throughout the period, while regional adaptations to environmental conditions and the consequent specialized lifestyles evolve. In the Southwest, farming becomes more important and pithouses and storage structures are grouped into villages. The influential presence of Mexico to the south continues to be felt. In the Eastern Woodlands, mound groups that include residential areas are initiated in locations adjacent to major rivers, and the cultural pattern subsequently known as Mississippian begins. In the Arctic, whales are successfully hunted and the presence of a new archery/armor complex implies serious competition for available resources.
500 Semi-subterranean chambers known as kivas are built in the Southwest, some used for ceremonial purposes.
500 The bow and arrow are in use on the Great Plains.
600 The population grows in the Southwest and cotton cultivation spreads northward from Mexico; regional differentiation develops and is reflected in the pottery styles.
750 Corn is increasingly present among native crops in the river valleys of the Midwest and Southeast.
800 In the central Mississippi region known as the American bottom, mound centerssome with structures placed around community plazasbecome politically dominant.
800 Pithouses give way to surface structures in the Southwest.
850 Intensive maize agriculture is practiced in the Southwest, and durable shell-tempered pottery is produced. Ballcourts are present at Snaketown in Arizona.
850 In the Arctic, settlements grow larger on St. Lawrence Island; a body armor and archery complex develops.
900 Construction of large multiroomed buildings, known as great houses, begins in Chaco Canyon in the central San Juan Basin of southwestern New Mexico.
950 Effigy-mound groups, representing animals and birds, are erected in the Midwest; Great Serpent Mound rises in Ohio.
1000 In the Mimbres Valley of New Mexico, a distictive type of ceramic decoration develops.