Virginia prohibits anyone with "a single drop of Negro blood" from marrying a white person.
Date: 1924
Anti-miscegenation laws continue to be passed as a surveillance method for racial and blood "impurities" throughout the 1920s. Louisiana bans marriage between Natives and African-Americans in 1920.
Then, in the Racial Integrity Act of 1924, Virginia specifies that "one drop" of "African-descended blood" is enough to prohibit a Black or mixed-race person from marrying a white person.