You might be interested in the FAQ section under "North America - Cities and Monumental Architecture". Previous answers there include:

Why are there no ancient Native American cities in North America? by /u/Reedstilt
Why are there no pyramids or temples in North America, but there are so many in South America? by /u/Reedstilt
The Natives of South and Central America always seem to have been incredibly ahead of their neighbours in North America. Why is that? by /u/Cozijo