The Mississippian People are known to have established massive urban cities on mounds that had trade routes going all over the Americas, since these 3 Cultures existed and peaked in population around the same time (600CE-1400CE) do you think they actively traded with each other? They shared a lot of Religious and Cultural traits like Human sacrifice and building of structures aligned with the stars. Also, the Iroquois League was formed and existed during this time period as well, do you think there was any connection between all these different Pre-contact American Cultures? I think the proximity between all of them would suggest so.
do you think they actively traded with each other?
Not as far as we can tell now. There's only one definitive Mesoamerican artifact found at a Mississippian site: a small obsidian tool found at Spiro in eastern Oklahoma. Ancient trade routes, going back well before the Aztecs, connected the American Southwest to central Mexico. There's considerable evidence for goods and ideas travelling back and forth along that route. A prominent example is Paquimé, an ancient city just south of the present day Mexico-New Mexico border, which once served as the gateway between the two regions--it's famous for its mix of Southwestern and Mesoamerican features, as well as the fact that people there used to raise parrots brought up from Central America.
Spiro likely got that bit of Mesoamerican obsidian from Southwestern trading partners, rather than from Mesoamerica directly. We have much better evidence for pre-Columbian contact between those two regions. Southwestern cotton cloth shows up at Spiro, for example. For whatever reasons, there doesn't appear to have been north-south trade routes crossing Texas (on a related not, the survivors of de Soto's expedition tried to return to Mexico City by crossing Texas but gave up on that route because they couldn't find enough food (or enough granaries to pillage) to sustain themselves on the trip. Cabeza de Vaca, after being shipwrecked on the coast of Texas, got a little further south but also ended up taking the long way around to get back to Mexico City.
They shared a lot of Religious and Cultural traits like Human sacrifice and building of structures aligned with the stars.
The role of human sacrifice among the Mississippians and in Mesoamerican cultures was very different. Mississippian sacrifices seem to have been part of their funerary traditions, rather than as offerings to the gods. As for archaeoastronomy, astronomical alignments are a fairly minor topic in Mississippian archaeology, especially compared to their local predecessors, the Hopewell, who seemed to have loved lunar alignments. Mississippian and Mesoamerican cultures are only distantly related.
Also, the Iroquois League was formed and existed during this time period as well, do you think there was any connection between all these different Pre-contact American Cultures?
The Haudenosaunee or pre-Haudenosaunee Iroquois (depending on the exact timing of the league's origins) almost certainly had contact with Mississippian cultures. Though their main Pre-Contact trade interests were the Great Lakes and the Hudson (for copper and wampum, respectively), the Allegheny and Ohio Rivers had also been a major trade route for the Haudenosaunee for centuries. Just like Cahokia was situated to take advantage of trade coming down the Mississippi and Missouri, the Mississippian culture at Angel Mound was situated to benefit from the trade coming down from the eastern Great Lakes via the Wabash and the Ohio. Between the Haudenosaunee and Angel Mound were two societies that, while not Mississippians themselves, were influenced by the Mississippians in various ways. In southwestern Ohio were the Fort Ancients (Ancestral Shawnee, but also possible connections with Dhegiha-speaking peoples), who incorporated Mississippian iconography into their religion, but didn't adopt the Mississippian political system. In southwestern Pennsylvania and parts of neighboring states were the Monongahela (who may have been the historic Massawomeck), an apparently Iroquoian-people with a notable fondness for the Mississippian sport of chunkey. They also linked Chesapeake Bay with the Middle Mississippian world via the Potomac River. While the Middle Mississippian polities had ceased to be Mississippians before contact, those trade routes remained in place and brought European goods to their successor polities long before Europeans themselves showed up in the interior.
I dunno how many good sources there are on this. The problem is, the evidence for such trade would be Aztec artifacts in Cahokia or vice versa. Considering though, that the Spanish were in contact with Mesoamericans and also traded with the Mississippians*; the artifacts would have to pre-date Spannish contact to be a slam dunk.
I'll be interested to see if anybody has good info on this.
