Arch Goins and family, Melungeons from Graysville. Archival family photograph from the 1920s
Arch Goins and family,
Melungeons from Graysville, Tennessee
"Whiteness" in the U.S. has value. It is no surprise that in a society that has historically oppressed, scorned and demonized "blackness" (as if blacks were almost an untouchable caste), some sub-cultural groups scattered across the nation sought refuge in elaborately constructed "not black" clusters. The United States government, mandated by the Constitution to collect census data that included "race" as a category, created much of the confusion, with shifting classifications over time, using terms like mulatto, octoroon, mestizo, and mixed. Some states also classified those people who were "not white" and not enslaved simply as "free people of color," which at times included Mexicans and Native Americans.
Clusters of people who were designated "not black," but historically "not white," were scattered across the U.S. All of these groups, dubbed by anthropologists and sociologists as "tri-racial isolates," or "maroons," are an interesting part of our troubled racialized history and current notions of "race," "ethnicity," ancestry, and genetics.  
One maroon group that has fascinated both social scientists and genealogists were named by outsiders (as a slur) and they now dub themselves with the same name: Melungeon. Their history and self-constructed folk mythology has been re-visited in recent years due to the advent of modern DNA research.