Which county has the highest mixed race population?

[memphis]

The racial data is all self-reported. The whole definition of racial identity is far from 100% objective for people of mixed ancestry. And plenty of people don't know their background. Nearly every black person has white ancestry if you go far enough back to get to the days of slave rape. And there's a fair amount of Native American descent floating around the gene pool too. There's no real way to answer this question.