Aztalan State Park is a Wisconsin state park in the Town of Aztalan, Jefferson County. Established in 1952, it was designated a National Historic Landmark in 1964 and added to the National Register of Historic Places in 1966. The park covers along the Crawfish River. Aztalan is the site of an ancient Mississippian culture settlement that flourished during the 10th to 13th centuries. The indigenous people constructed massive earthwork mounds for religious and political purposes. They were part of a widespread culture with important settlements throughout the Mississippi River valley and its tributaries. Their trading network extended from the Great Lakes to the Gulf Coast, and into the Southeast of the present-day United States. Pre-history (900–1300) Aztalan was first settled around 900 CE by a Native American culture known as the Middle Mississippian tradition. The chief center of a Middle Mississippian settlement is at Cahokia, in present-day Illinois, a city that at its peak had 20,000–30,000 people. This was not surpassed by Europeans in North America until after 1800. These settlements are characterized by the construction of earthwork mounds, stockades, and houses, by decorated Mississippian culture pottery, and agricultural practices. There are also elements of the Woodland culture found there. The residents of Aztalan had long-distance trading relationships with other settlements, linked by their use of the rivers for transportation. For example, items found at the settlement include copper from Michigan's Upper Peninsula, shells from the coast of the Gulf of Mexico, and stone such as Mill Creek chert from other areas of the Midwest. Sometime between 1200 and 1300 CE, the Aztalan settlement was abandoned. Archeologists and historians surmise they may have outgrown environmental resources, or encountered more warfare from other cultures, but do not know for sure. The Little Ice Age occurred soon after 1300 and may have contributed to farming difficulties, putting too much stress on the local chiefdoms. Life in Aztalan Most of the residents lived in circular or rectangular houses which they built between the river and the eastern secondary wall. The placement of the structures suggests that the layout was planned. The dwellings were built around a central ceremonial plaza likely used for rituals and public gatherings, as has been found at similar locations. Posts for the house frames were placed either in individual holes, or in a trench dug slightly narrower than the posts. The walls were completed with wattle and daub, a