Watson Brake is an archaeological site in Ouachita Parish, Louisiana from the Archaic period. Dated to about 5400 years ago (approx. 3500 BCE), Watson Brake is considered the earliest mound complex in North America. It is the earliest dated, complex construction in the Americas. It is an arrangement of human-made mounds located in the floodplain of the Ouachita River near Monroe in northern Louisiana, United States.