Final answer:
The best ethnographic evidence of chiefdoms is found in societies across the world, where such political structures concentrate various forms of power in the leadership of chiefs. Examples include settlements in the Mississippi River valley and complex political systems in African societies.
Step-by-step explanation:
Much of the best ethnographic evidence of chiefdoms is found in cultures across the world, including Africa, Oceania, the Middle East, Europe, East and Southeast Asia, North, Central, and South America. These chiefdoms often display a fusion of various forms of power in the position of a chief, combining economic, political, religious, and military authority. Examples of such chiefdoms with robust evidence can be seen in the archaeological remains of the Mississippi River valley in North America, where large settlements and extensive trading networks have been uncovered. Another notable example is found in African societies, where research has shown the existence of complex and moralized political systems with checks and balances.