The Mound Builders

 

Louisiana has some of the oldest mounds. Poverty Point and Watson Brake, which are supposed to be the oldest known mounds.

https://www.nationalgeographic.com/culture/article/150518-cahokia-ancient-America-prehistoric-floods-mystery-Mississippi

https://archive.archaeology.org/9801/newsbriefs/mounds.html

https://en.wikipedia.org/wiki/Watson_Brake

Poverty Point, La.  Long time thought to be oldest site.

Large mounds that were destroyed are used for fill. 

https://en.wikipedia.org/wiki/Sugarloaf_Mound

https://en.wikipedia.org/wiki/Troyville_Earthworks

https://www.stltoday.com/news/archives/a-look-back-big-mound-in-st-louis-legacy-of/article_3b006339-444d-575f-91c5-8b4f96fa08cd.html

Big Mound. St. Louis

Poverty Point artifacts.

https://en.wikipedia.org/wiki/Mound_Builders

LSU campus mounds in Baton Rouge.

Marksville, La. mound.

https://archive.archaeology.org/online/features/lamounds/

https://en.wikipedia.org/wiki/Marksville_Prehistoric_Indian_Site