The last American slaves lived well into the 20th century. 

We often hear that Black people should forget about slavery because it was so long ago. Even if it was 400 + years ago, we should never forget. However, slavery was not that long ago. It was so recent that many of the last slaves lived long enough to be recorded. Listen to the story of a few former slaves. Hughes was a former slave.

Hughes: ... Colored people that's free ought to be awful thankful. And some of them is sorry they are free now. Some of them now would rather be slaves.

Interviewer: Which had you rather be Uncle Fountain?

Hughes: Me? Which I'd rather be ? [interviewer laughs]

Hughes: You know what I'd rather do? If I thought, had any idea, that I'd ever be a slave again, I'd take a gun and just end it all right away. Because you're nothing but a dog. You're not a thing but a dog. Night never comed out, you had nothing to do. Time to cut tobacco, if they want you to cut all night long out in the field, you cut. And if they want you to hang all night long, you hang, hang tobacco. It didn't matter about your tired, being tired. You're afraid to say you're tired. They just, well [voice trails off].

Interview with Fountain Hughes, Baltimore, Maryland, June 11, 1949 | Library of Congress (loc.gov)