Let's see:
Northeastern North America: This is the climax of the Norse settlements in Greenland. It's possible that the Vikings were still trading with the mainland Native Americans at this time, but this is supposedly two centuries past the date of the short-lived Vinland settlement (possibly connected to L'Anse aux Meadows on the northern tip of Newfoundland.)
Most of the northeast is in the Late Woodlands era of cultural development, with a varying mix of true agriculture, horticulture, and hunting and gathering across the region. The Little Ice Age is beginning to trigger an amalgamation of smaller tribes into larger confederations. Most historians doubt the Iroquois Confederacy came into existence this early, though a few use an Iroquois oral legend that possibly refers to a total solar eclipse as evidence that they came together around 1142 AD.
Southeastern and Midwestern North America: This is height of the Mississippian culture, with stratified chiefdoms containing large, agricultural settlements and distinctive earthworks (hence the term "moundbuilders"). The largest and most impressive is Cahokia in Illinois, with Moundville in Alabama not far behind and Emerald Mound in Mississippi on the rise at this time.
Northwestern North America: The Pacific Northwest Coast is distinctive among world cultures for maintaining a hunting-and-gathering level of food production at a relatively high level of social stratification.
Southwestern North America: The Pueblo III culture of the Anasazi sees the abandonment of Chaco Canyon as a major spiritual center and the rise of Mesa Verde as its replacement, projecting influence onto outlying villages while indirectly absorbing indirect influence from Mesoamerica as local elites seek imported goods as status symbols (like scarlet macaw feathers and cacao beans). Other, neighboring settled cultures such as the Hohokam and Mogollon are also in their prime at this time. The nomadic Southern Athabascan peoples such as the Navajo and the Apache have not yet migrated this far south.