[X-fib]

In North America north of Mexico the oldest surviving buildings probably occur in the southwestern U.S. as Anatazi or similar culture dwellings and ceremonial centers. Elsewhere the oldest surviving "building" , if you can call them that, are Mississipian earthen platform mounds. The most noted of which are at the Cahokia World Hertitage Site near Collinsville, Illinois where the platform top pyrimid mound's construction period date to around 1000CE and are among the largest of their kind in the world. Elsewhere in middle N America , earthen burial and eiffgy mounds are considerably older.

As far as I know the oldest surviving man made "structures" in the America's may be stone cobble fish wiers (dams). Many examples of which survive in North America's Great Lakes region. Although reliable dates are lacking for their initial construction the earliest probably date to the Early to Middle Archaic Tradition appromixately 4,000 to 8,000 years BP. They were still used by Native Americans and early commerial fisherman in the 19th century CE.